20mm FlipTop® Optima Flip-Off Seal

Name: 20mm FlipTop® Optima Flip-Off Seal
Brand: Autofits

The 20mm FlipTop® Optima is the highest-volume aluminium-plastic flip off seal in the range: an AA8011 aluminium shell crimped over the rubber stopper with a moulded polypropylene button you flip up to expose a central injection point. Total seal height is 9.02 to 9.91 mm, with six tapered bridges and a maximum opening force of 35 N, made to ISO 8362-6.

This page gives the 20 mm dimensions, materials, quality position, applications and ordering. For the full range and design options, see the FlipTop® Optima product page.

Key takeaways

The 20mm Optima is the most widely used flip-off seal size for injectable vials.
Total seal height 9.02–9.91 mm, inner aluminium Ø 20.22 mm (min), outer disc Ø 23.14 mm (max).
Six tapered bridges; maximum opening force 35 N.
Standard packing is 6,000 per box (2,000 × 2 bags); Tyvek bagging available.
Aluminium AA8011 with epoxy lacquer; polypropylene button moulded in-house on Toyo machines.
Made under ISO 15378, ISO 9001 and ISO 14001 with a Drug Master File, 100% camera inspected.

What is the 20mm FlipTop® Optima?

The 20mm Optima is the standard flip-off seal for 20 mm neck vials, the most common injectable vial format and the highest-volume size in the Optima range. The deep-drawn aluminium shell crimps under the vial neck flange to compress the rubber stopper against the glass, forming the sterile barrier. The polypropylene button on top is flipped up at point of use to expose a small central area of the stopper for the needle, while the aluminium stays crimped and the seal stays intact.

It is one of five sizes in the Optima range (13, 20, 28, 32 and 34 mm), and by far the most specified. Match the 20 mm seal to a 20 mm vial finish and a 20 mm stopper of the same nominal diameter; vial necks follow ISO 8362-1. For smaller and larger formats, see the 13mm and 28mm Optima.

Specifications and sizing

Controlled dimensions for the 20 mm Optima, 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
Inner Ø aluminium seal (D1)	20.22 mm (min)
Outer Ø disc (D2)	23.14 mm (max)
Disc height	3.20–3.60 mm
Inner aluminium height	7.37–7.62 mm
Total seal height	9.02–9.91 mm
Aluminium thickness	0.16–0.20 mm
Bridges	6 taper
Max opening force	35 N
Standard packing (per box)	6,000 (2,000 × 2 bags)

Top designs are Bridge, Button (intrinsic tamper evidence, with a 12-stem flower under the button disc) and Flower. Finishes are glossy, matte, embossed or printed, in a wide range of colours customised to requirement.

Materials and quality

The shell is AA8011 aluminium alloy (EN 15088:2005, EN 10204 3.1, tested to BS EN 485-2:2008; REACH and RoHS compliant) with an epoxy lacquer coating to 21 CFR 175.300. The button is polypropylene to 21 CFR 177.1520, moulded in-house on Japanese Toyo injection-moulding machines and assembled in an ISO Class 8 cleanroom. Heavy metals are held to a maximum 100 ppm total and the components are BSE/TSE-free (EMEA/410/01 rev. 3).

Every seal passes 100% high-speed camera inspection. 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, in the 75,000 sq ft Nashik facility. AQL: critical nil, major not more than 2.5%, minor not more than 4%. See the quality page, ISO 8362-6 and ISO 15378.

Forms of supply

The 20 mm Optima ships Regular (non-sterile), Ready-to-Use (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 before capping for RTU. Minimum order quantities and lead times are available on request.

Applications

The 20 mm Optima is the workhorse closure for routine injectable and parenteral vials, including liquid and lyophilised products, where colour coding differentiates strengths or where intrinsic tamper evidence is required (the Button design). It is the default choice for most 20 mm filling lines. Browse comparable closures on the 20 mm by-size index.

FAQ

What is the total height of a 20mm flip-off seal?

The 20 mm FlipTop® Optima has a total seal height of 9.02 to 9.91 mm, with an inner aluminium height of 7.37 to 7.62 mm and a disc height of 3.20 to 3.60 mm. The inner aluminium diameter is 20.22 mm minimum and the outer disc diameter is 23.14 mm maximum.

What is the opening force of the 20mm Optima?

The maximum opening force for the 20 mm Optima is 35 N. It has six tapered bridges; opening force varies with the number of bridges in the design.

How many 20mm 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 × 270 × 320 mm shipper. Tyvek bagging is available as an alternative.

Why is 20mm the most common flip-off seal size?

The 20 mm neck is the most widely used finish for injectable vials, so the 20 mm flip-off seal is the highest-volume size across the industry and in the Optima range. It suits the bulk of routine liquid and lyophilised injectables.

Is the 20mm seal available sterilized?

Yes. It is offered Ready-to-Use, sterilized by gamma irradiation or ETO and supplied double-bagged for aseptic filling, as well as Ready-to-Sterilize and Regular. RTU seals are washed and assembled in an ISO Class 8 cleanroom.

Sources

Autofits FlipTop Seals dossier and engineering drawings (working/spec-sheets/)
ISO: ISO 8362-6:2010, Caps made of aluminium-plastics combinations for injection vials (https://www.iso.org/standard/45641.html)

*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.*