20mm FlipTop® Pull-Ring Seal

Q: What is the height of a 20mm pull-ring seal?

Total assembled height is 9.00 to 10.00 mm: an inner aluminium section 7.00 to 7.60 mm high and a polypropylene disc 3.00 to 4.00 mm high. Inner aluminium diameter is 20.00 to 20.60 mm and outer disc diameter is 22.00 to 23.00 mm.

The 20mm FlipTop® Pull-Ring is an aluminium-plastic combination seal for 20 mm neck vials that comes away whole: the operator pulls the aluminium ring and turns it anticlockwise, and the seal detaches once the polypropylene disc is detached. Assembled height is 9.00 to 10.00 mm, the design carries six taper bridges, maximum opening force is 35 N, and standard packing is 6,000 seals per box. The drawing carries a “For Oral Use Only” marking, which is what routes this size to oral-medicine presentations.

Autofits is one of the few manufacturers of pull-ring seals in India. The mechanism and the wider family are on the FlipTop® Pull-Ring page, and every closure family Autofits makes is indexed on the products overview.

Key takeaways

The 20 mm pull-ring removes the whole seal by hand, single-handed, with no decapper or crimp tool.
The drawing carries a “For Oral Use Only” marking, which directs the closure to oral-medicine use.
Assembled height 9.00–10.00 mm, inner aluminium Ø 20.00–20.60 mm, outer disc Ø 22.00–23.00 mm.
Six taper bridges; maximum opening force 35 N.
Standard packing is 6,000 per box (2,000 × 2 bags) in a 420 × 270 × 320 mm shipper.

What is the 20mm FlipTop® Pull-Ring seal?

The 20 mm pull-ring is an aluminium-plastic combination cap that crimps over the rubber stopper of a 20 mm neck vial and is opened by pulling an aluminium ring and rotating it anticlockwise, so the whole seal detaches once the polypropylene disc is detached. The AA8011 shell holds the stopper compressed against the glass, a moulded polypropylene disc sits on top in a six-bridge configuration, and an aluminium ring is presented at the surface as the grip.

The mechanism separates it from a flip-off seal. On a flip-off, only a small plastic button lifts, exposing an injection point while the aluminium skirt stays crimped. On the pull-ring, the whole closure leaves the vial, opening the full mouth for pouring or reconstituting a dose, single-handed. A detached seal cannot be reseated.

Match the seal to a 20 mm vial finish and a 20 mm stopper of the same nominal diameter; vial necks follow ISO 8362-1. The wide-neck version is the 32 mm pull-ring.

The “For Oral Use Only” marking

The 20 mm pull-ring drawing carries a “For Oral Use Only” marking on the disc, so the route of administration is printed on the closure itself rather than left to the carton. The dossier records the family as often marked “For Oral Use Only / Flip Top & Tear”. The marking tells the operator the product is not for needle access through a retained button, at the moment the vial is handled rather than in a leaflet. Where oral-medicine presentations sit next to injectable vials of the same 20 mm size, that on-part instruction is a practical differentiator.

Specifications and sizing

Controlled dimensions from the Autofits engineering drawings, with maximum opening force and standard packing. The standard shipper box is 420 × 270 × 320 mm.

Property	Value
Nominal size	20 mm
Construction	Aluminium-plastic combination
Design	Bridge
Inner Ø aluminium seal (D1)	20.00–20.60 mm
Outer Ø disc (D2)	22.00–23.00 mm
Disc height	3.00–4.00 mm
Inner aluminium height	7.00–7.60 mm
Total / assembled height	9.00–10.00 mm
Aluminium thickness	0.18–0.22 mm
Bridges	6 taper bridges
Marking	For Oral Use Only
Max opening force	35 N
Standard packing (per box)	6,000 (2,000 × 2 bags)

Opening force varies with the number and geometry of the bridges. Finishes are glossy or matte in a wide range of colours; colour codes, order quantities, pricing and lead times are available on request.

Materials and quality

The shell is AA8011 aluminium alloy (EN 15088:2005, EN 10204-3.1, REACH and RoHS compliant) with an epoxy lacquer coating to 21 CFR 175.300 that may be pigmented for colour. The disc is polypropylene to IS 10910 / IS 10909 and FDA 21 CFR 177.1520, moulded in-house on Japanese Toyo machines. Heavy metals are held to not more than 100 ppm total and the parts are BSE/TSE-free to EMEA/410/01 rev. 3.

Aluminium is washed on an automated line, every seal passes 100% high-speed camera inspection, and assembly is in an ISO Class 8 cleanroom at the 75,000 sq ft Nashik plant. Production runs under ISO 15378:2017 GMP with ISO 9001:2015 and ISO 14001:2015 certification, a Drug Master File (DMF 18100) and CFDA registration B20200000501. AQL is critical nil, major not more than 2.5%, minor not more than 4%. See ISO 8362-6, the standard for aluminium-plastics combination caps.

Forms of supply

The 20 mm pull-ring ships Regular (non-sterile bulk), Ready-to-Use (assembled and washed in the ISO Class 8 cleanroom, gamma or ETO sterilized, double-bagged for aseptic areas) and Ready-to-Sterilize. Shelf life is 3.5 years before capping for non-irradiated seals, plus 5 years after capping, and 2 years for Ready-to-Use. Tyvek bagging is an option.

Applications

The 20 mm pull-ring suits oral-medicine presentations and reconstituted products, where the whole seal is removed by hand and the full vial mouth is needed. Oral liquids and suspensions are the core case: the dose is poured or drawn rather than injected, so a retained injection point has no value. Products reconstituted before administration fit the same pattern.

The alternative at this size is the 20 mm tear-down, where the riveted disc is opened before being turned; the two are compared in pull-ring vs tear-down seals. Every 20 mm construction is on the 20 mm by-size index.

Frequently asked questions

What is the height of a 20mm pull-ring seal?

Total assembled height is 9.00 to 10.00 mm, with an inner aluminium section 7.00 to 7.60 mm high and a disc 3.00 to 4.00 mm high. Inner aluminium diameter is 20.00 to 20.60 mm and outer disc diameter is 22.00 to 23.00 mm.

How do you open a 20mm pull-ring vial seal?

Lift the aluminium ring, pull it, and rotate it anticlockwise. The whole seal detaches once the polypropylene disc is detached, so the aluminium and the disc come away together and the vial mouth is exposed. No crimp tool or decapper is needed.

Why is the 20mm pull-ring marked For Oral Use Only?

The 20 mm pull-ring drawing carries a For Oral Use Only marking on the closure. The design is built for the whole seal to lift away rather than for needle access through a retained button, so the marking directs the product to oral-medicine use. This matters where oral and injectable presentations share the same 20 mm neck size.

How many 20mm pull-ring seals are in a box?

Standard packing is 6,000 seals per box, supplied as 2,000 in each of two bags, in a 420 by 270 by 320 mm shipper. Maximum opening force is 35 N and the design carries six taper bridges. Tyvek bagging is available as an alternative.

What is the difference between a 20mm pull-ring and a 20mm tear-down seal?

Both remove the whole seal rather than a button, and both are aluminium-plastic combinations in the same 20 mm neck size. On the pull-ring, the operator pulls an aluminium ring and turns anticlockwise. On the tear-down, the riveted disc is opened first, then pulled and rotated anticlockwise. Both are quoted at 35 N.

Sources

ISO 8362-6:2010, Caps made of aluminium-plastics combinations for injection vials (https://www.iso.org/standard/52806.html)
ISO 15378:2017, Primary packaging materials for medicinal products, GMP requirements (https://www.iso.org/standard/70729.html)
Autofits engineering drawings and FlipTop Seals dossier (internal, on file)

*Last updated: 2026-08-18. 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.*