FlipTop® Cap: Aluminium-Plastic Seals for Pharmaceutical Vials

FlipTop® Aluminium-Plastic Seals for Pharmaceutical Vials | Autofits

A FlipTop® cap is an aluminium-plastics combination vial seal: an aluminium shell crimps over the rubber stopper while a polypropylene (PP) disc or button sits on top. Autofits builds the FlipTop® family in three opening actions, flip-off (Optima), pull-ring and tear-down, all to ISO 8362-6 for aluminium-plastics combination caps.

This is the hub for the whole FlipTop® range. Use the comparison below to choose the opening action you need, then follow the links into each variant for dimensions and ordering detail, or jump to the size hub to match a cap to your vial neck finish.

Key takeaways

A FlipTop® cap is an aluminium-plastics combination: an aluminium seal plus a PP disc or button, built to ISO 8362-6.
The family has three opening actions: flip-off (Optima), full removal by pull ring, and twist-off (Tear-Down).
Optima comes in Bridge, Button and Flower designs and Glossy, Matte, Embossed and Printed finishes; the Button design carries intrinsic tamper evidence.
The PP top gives a clean opening action plus a surface for colour-coding and printing; colours are available in a wide range, matte or glossy, customised to requirement.
Sizes span 13 to 34 mm depending on the variant; see the size hub for which design comes in each size.
All variants are produced under ISO 9001, ISO 14001 and ISO 15378, with in-house Toyo PP moulding and 100% camera inspection.

How the aluminium-plastics combination is built

A FlipTop® cap is two materials working together. The lower part is an aluminium shell, formed from alloy AA8011 and epoxy-lacquered, that is rolled under the vial neck flange during capping. This crimp compresses the rubber stopper against the glass and forms the sterile barrier; it is the same sealing action used across every vial seal.

The top is a polypropylene (PP) disc or button, moulded in-house on Japanese Toyo injection machines and seated into the aluminium. The plastic top is what the user interacts with: depending on the design, it flips, pulls or twists. It also gives the cap a clean coloured surface for colour-coding and printing, which the all-aluminium seals cannot match as easily.

This two-material build is the aluminium-plastics combination covered by ISO 8362-6. It is the most common closure on modern injectable vials because it pairs a reliable metal crimp with an easy, clean opening action.

Compare the FlipTop® variants

Variant	Construction	Opening action	Sizes	Tamper evidence	Typical use
Optima (flip-off)	Aluminium shell + PP button disc	Flip the button up to expose the injection point	13, 20, 28, 32, 34 mm	Visible once button is flipped; Button design has intrinsic tamper evidence	Routine injectables; colour-coding
Pull Ring	Aluminium shell + PP disc with pull ring	Pull the ring, open anticlockwise; whole seal detaches	20 mm (bridge), 32 mm (flower)	Whole seal detaches once disc is detached	Full-seal removal; often marked for oral use
Tear-Down	Aluminium shell + PP disc riveted to alu	Twist the disc anticlockwise; the seal tears down and off	13, 20, 32 mm	Seal tears down and lifts clear	Mainly oral vaccinations

Optima designs and finishes

The flip-off Optima is the workhorse of the range, and it is offered in several designs and finishes.

Designs:

Bridge design, with tapered bridges holding the button.
Button design, a 12-stem flower under a button disc, which gives intrinsic tamper evidence.
Flower design, used on the larger sizes.

Finishes:

Glossy
Matte
Embossed
Printed

Colours are available in a wide range, matte or glossy, customised to requirement. The choice of design and finish does not change the sealing action; the aluminium crimp is what holds the stopper. Full Optima dimensions, bridge counts and opening forces are on the Optima page.

Sizing reference

FlipTop® seals are specified by the vial neck finish, not the vial’s nominal volume. Match the seal size to the neck finish, which follows ISO 8362-1. The flip-off Optima covers the widest size span, 13 to 34 mm, while the pull-ring and tear-down designs are made in the sizes shown in the table above. For inner diameters and total heights at each size, use the size hub and the individual variant pages.

Quality and standards

FlipTop® seals are built to ISO 8362-6 (aluminium-plastics combination caps) under an ISO 15378:2017 quality system, alongside ISO 9001:2015 and ISO 14001:2015 certification, a Drug Master File (DMF 18100) and a CFDA registration (B20200000501).

The aluminium is alloy AA8011 with an epoxy lacquer coating (21 CFR 175.300); the PP disc conforms to IS 10910/IS 10909 and FDA 21 CFR 177.1520 for olefin polymers, with BADGE, NOGE and BFDGE not used. Materials are REACH and RoHS compliant and BSE/TSE-free. PP discs are moulded in-house on Toyo machines, washed in a fully automated line, assembled in the ISO Class 8 cleanroom, and 100% camera inspected. Seals are available Regular, Ready-to-Use (RTU, gamma or ETO sterilised) or Ready-to-Sterilise (RTS). See the quality page and ISO 15378.

Frequently asked questions

What is a FlipTop® cap?

A FlipTop® cap is an aluminium-plastics combination vial seal. An aluminium shell crimps over the rubber stopper to seal the vial, and a polypropylene disc or button sits on top to give the opening action. It is the type of seal covered by ISO 8362-6. Autofits makes it in flip-off (Optima), pull-ring and tear-down designs.

What is the difference between the Optima, Pull-Ring and Tear-Down designs?

The Optima flips a plastic button up to expose a small injection point while the aluminium stays crimped. The Pull-Ring lets the whole seal come away once the disc is detached: you pull the ring and open anticlockwise. The Tear-Down twists anticlockwise so the seal tears down and lifts clear, and is used mainly for oral vaccinations.

What designs and finishes are available on the Optima?

The Optima comes in Bridge, Button and Flower designs, with Glossy, Matte, Embossed and Printed finishes. The Button design gives intrinsic tamper evidence through a 12-stem flower under a button disc. Colours are available in a wide range, matte or glossy, customised to requirement.

What sizes do FlipTop® seals come in?

The flip-off Optima covers 13, 20, 28, 32 and 34 mm. The Pull-Ring is made in 20 mm (bridge) and 32 mm (flower). The Tear-Down is made in 13, 20 and 32 mm. There is no 30 mm size. See the size hub for dimensions at each size.

Can FlipTop® seals be supplied sterile?

Yes. They are available Regular, Ready-to-Use (RTU) or Ready-to-Sterilise (RTS). RTU seals are assembled in the ISO Class 8 cleanroom, washed, double-bagged and gamma or ETO sterilised for aseptic filling.

Sources

ISO: ISO 8362-6, Injection containers and accessories, Part 6: Caps made of aluminium-plastics combinations for injection vials (https://www.iso.org/)
ISO: ISO 8362-1, Injection containers and accessories, Part 1: Injection vials made of glass tubing (https://www.iso.org/)
ISO: ISO 15378, Primary packaging materials for medicinal products, GMP requirements (https://www.iso.org/standard/70794.html)
Autofits product master spec data (engineering drawings and FlipTop Seals dossier)

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