Aluminium Pilfer-proof Caps

An Autofits pilfer-proof cap is a roll-on pilfer-proof (ROPP) aluminium closure for threaded bottles: it is supplied as a smooth threadless aluminium shell whose threads are roll-formed onto the bottle neck during capping, with a lower pilfer band that shears on first opening and cannot be reattached. The caps are all-aluminium, epoxy-lacquer lined, printable and colourable, and are made in common ROPP sizes including 22, 25, 28 and 35 mm at the Autofits facility in Nashik, India.

This page sets out the pilfer-proof (ROPP) range for formulators, packaging engineers and sourcing managers: how the cap works, the sizes offered, materials and manufacturing, the quality and regulatory position, supply forms, applications, how it compares with crimped flip-off vial seals, and how to order.

Key takeaways

• A pilfer-proof cap is a roll-on pilfer-proof (ROPP) aluminium screw cap with a tear-off pilfer band that gives permanent, irreversible tamper evidence.
• It ships as a smooth threadless aluminium shell; threads are roll-formed onto the bottle neck during capping, and the lower band is locked under the bottle bead.
• The pilfer band is joined to the cap body by thin bridges that shear on first opening; once broken, the band cannot be reattached.
• The caps are all-aluminium with an epoxy lacquer lining, and can be coloured, printed or embossed.
• Offered in common ROPP sizes including 22, 25, 28 and 35 mm; the exact size range and dimensions are available on request.
• Made under ISO 9001, ISO 14001 and ISO 15378 with a Drug Master File (DMF 18100), in a 75,000 sq ft Nashik facility with an ISO Class 8 cleanroom and 100% camera inspection.
• Pilfer-proof caps are distinct from injection-vial flip-off seals: see pilfer-proof cap vs flip-off seal.

What is a pilfer-proof (ROPP) cap?

A pilfer-proof cap is an aluminium screw closure for threaded bottles, designed so that the first opening leaves obvious, irreversible evidence that the seal has been broken. It is almost always a ROPP cap, short for roll-on pilfer-proof, because of how it is applied: the cap is not threaded when it is delivered.

The cap arrives as a plain aluminium shell, a cylinder closed at the top with a sealing liner inside and a knurled skirt, with a lower pilfer band connected to the body by thin bridges across a perforation. During capping, the shell is placed over the bottle neck and forming rollers press the soft aluminium into shape: thread rollers iron the metal into the bottle's thread profile, and a pilfer roller tucks the lower edge under the retaining bead on the neck. This is the roll-on, pilfer-proof process that gives ROPP its name.

Because the threads are formed against the actual bottle, the fit is tight and the band is captured beneath the bottle's bead. The first time the cap is unscrewed, the band cannot lift over the bead; the bridges shear, and the band stays behind or hangs loose while the cap comes off. A broken or missing band is then visible to a patient or consumer before use. The cap itself opens and recloses on its threads like any screw cap, so the container stays reclosable while the tamper evidence is one-time.

For a plain-English primer, see what is a pilfer-proof cap; for the formal definition, see the pilfer-proof cap glossary entry.

Sizes

Autofits supplies pilfer-proof (ROPP) caps in common ROPP sizes including 22, 25, 28 and 35 mm; the exact size range and dimensions are available on request. A pilfer-proof cap is specified by its diameter and the bottle neck finish it is rolled onto, so the cap size has to match the bottle's screw-neck finish.

Because each ROPP cap is matched to a specific bottle neck profile, dimensional drawings are confirmed per application rather than published as a single fixed table. Tell us your bottle neck finish and we will confirm the cap size and supply the dimensional drawing for it.

Materials

The Autofits pilfer-proof cap is an all-aluminium closure with an epoxy lacquer lining, selected and tested for pharmaceutical packaging duty. It carries no plastic component; the tamper evidence is built into the aluminium shell itself.

• Aluminium: alloy AA8011, conforming to EN 15088:2005, supplied with EN 10204 3.1 certification and tested to BS EN 485-2:2008. REACH and RoHS compliant.
• Lacquer: epoxy lacquer coating conforming to 21 CFR 175.300; it may be pigmented for colour.
• Heavy metals: chrome-VI, cadmium, mercury and lead held to a maximum 100 ppm total (EN 602, EC 94/62).
• BSE/TSE-free: per EMEA/410/01 rev. 3.

The aluminium is the same parenteral-grade AA8011 used across the Autofits seal range, so the material, lacquer and heavy-metal positions are consistent with the FlipTop seals and tear-off ranges.

Manufacturing and quality

Pilfer-proof caps are produced under an ISO 15378:2017 GMP quality system, with 100% camera inspection before packing. Production runs in the Autofits Packaging Pvt. Ltd. 75,000 sq ft facility in Nashik, India, which includes an ISO Class 8 cleanroom and a fully automated washing line to control particulates. Every cap passes 100% high-speed camera inspection.

The quality and regulatory position:

• Quality system: ISO 9001:2015, ISO 14001:2015 and ISO 15378:2017 (GMP for primary packaging materials); see ISO 15378.
• Regulatory filings: Drug Master File (DMF 18100) and CFDA registration (B20200000501).
• Food-contact and material compliance: epoxy lacquer to 21 CFR 175.300.
• Heavy metals: maximum 100 ppm total (EN 602, EC 94/62).
• BSE/TSE-free: per EMEA/410/01 rev. 3.

The full certification set is on the quality page.

AQL and inspection

Caps are released against a defined Acceptable Quality Level plan, applied on top of 100% camera inspection: critical defects nil; major defects not more than 2.5%; minor defects not more than 4%. The AQL plan is tailorable to customer specification.

Forms of supply

Pilfer-proof caps ship in three forms to match your line: Regular, Ready-to-Use and Ready-to-Sterilize.

• Regular: caps for customers who sterilize in-house or do not require a sterilized closure.
• Ready-to-Use (RTU): washed to control particulates and sterilized by gamma irradiation or ETO, supplied double-bagged for clean areas.
• Ready-to-Sterilize (RTS): cleaned and bagged for the customer's own sterilization step.

Tyvek bagging is available where required. Confirm the supply form with your order so we can specify the correct packing.

Applications

Pilfer-proof caps suit any threaded pharmaceutical bottle that needs visible, irreversible tamper evidence and a reclosable cap. Typical uses include:

• Oral liquids and syrups: where tamper evidence supports patient safety on reclosable bottles.
• Diagnostics and reagent bottles: liquids dispensed from threaded containers, including research-use reagents.
• General pharmaceutical liquids: bottled fluids where a secure, evident seal matters.

These are distinct from injectable vials, which take crimped flip-off seals rather than threaded caps; the applications hub covers the injectable side. Where the product is a sterile injectable in a stoppered vial, see the FlipTop Optima flip-off seal instead.

How pilfer-proof caps compare with flip-off vial seals

A pilfer-proof cap is a threaded, reclosable screw cap for bottles; a flip-off seal is a crimped, single-access seal for injectable vials. Both are aluminium-based and both give tamper evidence, but they close different containers in different ways. Note that the bridge, button and flower vocabulary used for the flip-off range does not apply to ROPP caps; a pilfer-proof cap's tamper evidence is its tear-off band, not a flipped plastic top.

For a side-by-side, see pilfer-proof cap vs flip-off seal.

Ordering

Pilfer-proof caps are specified by bottle neck finish, size, finish (plain, coloured, printed or embossed) and form of supply. Exact dimensional drawings per size are available on request, so send your bottle neck finish and we will confirm the matching cap and supply its drawing.

For minimum order quantities and lead times, contact us with your size, neck finish, colour reference, any print or emboss artwork, and required form of supply, and we will confirm MOQ and lead time.

FAQ

What is a pilfer-proof cap?

A pilfer-proof cap is an aluminium screw cap for threaded bottles with a tear-off band at its base that breaks the first time the container is opened, giving permanent tamper evidence. It is usually a ROPP (roll-on pilfer-proof) cap, supplied as a smooth threadless shell whose threads are formed onto the bottle neck during capping. A broken or missing band shows that the container has been opened.

What does ROPP stand for?

ROPP stands for roll-on pilfer-proof. It describes an aluminium cap supplied as a plain threadless shell that has its threads rolled, or formed, directly onto the bottle neck during capping, while the tamper-evident pilfer band is locked under the bottle bead at the same time.

What sizes do Autofits pilfer-proof caps come in?

Autofits supplies pilfer-proof (ROPP) caps in common ROPP sizes including 22, 25, 28 and 35 mm. The exact size range and dimensions are available on request, because each cap is matched to a specific bottle neck finish. Tell us your neck finish and we will confirm the size and supply the dimensional drawing.

Is a pilfer-proof cap reclosable?

Yes. Because the threads are formed onto the bottle, a pilfer-proof cap screws back on after opening and can reseal the container. The tamper evidence is one-time: once the band has broken on first opening it stays broken, but the cap itself can be removed and replaced like any screw cap.

What are pilfer-proof caps made of?

Autofits pilfer-proof caps are all-aluminium, made from AA8011 alloy with an epoxy lacquer lining conforming to 21 CFR 175.300. They carry no plastic component. Heavy metals are held to a maximum 100 ppm total, the aluminium is REACH and RoHS compliant, and the caps are BSE/TSE-free per EMEA/410/01 rev. 3.

How is a pilfer-proof cap different from a flip-off seal?

A pilfer-proof cap is threaded and reclosable, used on screw-neck bottles, and shows tamper evidence through a tear-off band. A flip-off seal is crimped over a rubber stopper on an injectable vial, is not reclosable, and shows tamper evidence through its flipped plastic button. The bridge, button and flower designs of the flip-off range do not apply to ROPP caps.

Can the caps be coloured or printed?

Yes. Pilfer-proof caps can be supplied plain, coloured, printed or embossed for branding and differentiation. The epoxy lacquer can be pigmented for colour. Send a colour reference and any artwork with your enquiry; exact colour lists and codes are confirmed per order.

What is the minimum order quantity?

Minimum order quantities and lead times depend on size, neck finish, finish and form of supply. They are available on request; contact us with your specification and we will confirm MOQ and lead time.

Related reading

• What is a pilfer-proof cap?
• Pilfer-proof cap: definition
• Pilfer-proof cap vs flip-off seal
• FlipTop aluminium-plastic seals
• All Autofits products
• ISO 15378: GMP for primary packaging

Sources

• Autofits FlipTop Seals dossier and engineering drawings (working/spec-sheets/)
• ISO: ISO 15378:2017, Primary packaging materials for medicinal products, GMP requirements (https://www.iso.org/standard/70729.html)
• World Health Organization: Substandard and falsified medical products (https://www.who.int/health-topics/substandard-and-falsified-medical-products)

*Last updated: 2026-06-26. This page is general technical and product information, not regulatory or compliance advice; confirm current standard editions and your own specification with Autofits and the issuing bodies.*