Bridge Type Seal With Groove: FlipTop® Optima Design

Bridge Type Seal With Groove | FlipTop® Optima | Autofits

The Bridge Type (With Groove) is the standard FlipTop® Optima design carrying an added groove feature: an AA8011 aluminium shell crimped over the rubber stopper, a moulded polypropylene button held on tapered bridges you flip up to expose a central injection point, and a groove that aids a clean crimp and a clean button release. It is the classic tapered-bridge flip-off top, with six tapered bridges at 13 and 20 mm, eight at 28 mm and twelve at 32 mm, made to ISO 8362-6.

This page gives packaging engineers, formulators and sourcing managers the design explanation, the sizes and controlled dimensions, materials, quality position, applications and ordering. For the design without the groove, see the Bridge Type (Without Groove); for the full range, see the FlipTop® Optima product page.

Key takeaways

The Bridge design is the core Optima top pattern: a flip button held on tapered bridges that shear away as the button is lifted.
The groove is a forming feature that helps the shell seat and crimp cleanly and helps the button release cleanly; it does not change the sealing principle or the tamper behaviour.
Bridge count scales with size: six tapered bridges at 13 and 20 mm, eight at 28 mm, twelve at 32 mm.
Spec basis here is the with-groove drawings for 20, 28 and 32 mm; total seal height runs 9.02 to 15.50 mm across those sizes.
Materials: AA8011 aluminium with epoxy lacquer and a polypropylene button moulded in-house on Toyo machines, assembled in an ISO Class 8 cleanroom.
Made under ISO 15378, ISO 9001 and ISO 14001 with a Drug Master File, 100% camera inspected.

What is the bridge type with groove?

The Bridge design is the standard Optima flip-off construction: the polypropylene button sits over a central aluminium disc connected to the shell by narrow tapered bridges. When the user flips the button up, the bridges shear cleanly, the button and central disc come away, and a small central area of the rubber stopper is exposed for the needle. The rest of the aluminium stays crimped under the vial-neck flange, so the stopper stays compressed against the glass and seal integrity is preserved. The number of bridges is matched to the seal diameter so the opening force stays controlled as the crown gets larger.

The “with groove” variant adds a groove feature to the crown. The groove assists the deep-draw and crimp so the shell seats consistently on the vial finish, and it supports a clean, predictable button release at point of use. Groove dimensions are held on the controlled drawing and are available on request; the sealing and tamper behaviour is the same as the standard bridge design. The general flip-off action is described on the flip-off seal glossary page.

How it differs from the other Optima designs

The Optima top comes in four designs, all on the same aluminium-plastic construction:

Bridge type with groove (this page): tapered-bridge flip-off top with a groove feature.
Bridge type without groove: the same tapered-bridge top without the groove.
Button type: carries intrinsic tamper evidence, with a 12-stem flower formed under the button disc so the opened state is visibly distinct.
Flower type: the flower top pattern within the Optima range.

Sizes and specifications

Controlled dimensions for the with-groove bridge design, from the Autofits engineering drawings, with maximum opening force and standard packing. The standard shipper box is 420 × 270 × 320 mm. Opening force varies with the number of bridges in the design.

Property	20 mm	28 mm	32 mm
Inner Ø aluminium seal (D1)	20.22 mm (min)	27.60–28.20 mm	32.10–32.90 mm
Outer Ø disc (D2)	23.14 mm (max)	30.10–31.10 mm	35.50–36.50 mm
Total seal height	9.02–9.91 mm	11.06–12.06 mm	14.30–15.50 mm
Aluminium thickness	0.16–0.20 mm	0.17–0.23 mm	0.21–0.25 mm
Bridges	6 taper	8	12 taper
Max opening force	35 N	35 N	65 N
Standard packing (per box)	6,000 (2,000 × 2 bags)	3,000 (1,500 × 2 bags)	1,400 (700 × 2 bags)

For 20 mm, the disc height is 3.20–3.60 mm and the inner aluminium height is 7.37–7.62 mm; for 28 mm the inner aluminium height is 8.70–9.30 mm. Remaining per-size heights are available on request. The bridge design also runs at 13 mm (six tapered bridges); its dimensions are on the 13mm size page. Per-size detail pages: 20mm, 28mm and 32mm. Tyvek bagging is available as an alternative to standard polybag packing.

Finishes are glossy, matte, embossed or printed, in a wide range of colours, matte or glossy, customised to requirement. Colour coding options are on the colours page.

Materials and quality

The shell is AA8011 aluminium alloy (EN 15088:2005, EN 10204 3.1 certification, tested to BS EN 485-2:2008; REACH and RoHS compliant) with an epoxy lacquer coating to 21 CFR 175.300, which may be pigmented for colour. The button is polypropylene to IS 10910 / IS 10909 and FDA 21 CFR 177.1520, moulded in-house on Japanese Toyo injection-moulding machines. Heavy metals (chrome-VI, cadmium, mercury, lead) are held to a maximum 100 ppm total, and components are BSE/TSE-free per EMEA/410/01 rev. 3.

Components are washed on a fully automated line to control particulates, assembled in an ISO Class 8 cleanroom, and every seal passes 100% high-speed camera inspection before packing. 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, at the Autofits Packaging Pvt. Ltd. 75,000 sq ft facility in Nashik, India. The design follows ISO 8362-6 for aluminium-plastics combination caps; the quality system is described under ISO 15378. AQL: critical nil, major not more than 2.5%, minor not more than 4%, tailorable to customer specification.

Applications

The bridge design is the general-purpose flip-off closure for injectable and parenteral vials: routine liquid injectables, lyophilised products, diluents and larger-volume parenterals in the 28 to 32 mm sizes, including vaccines and biologics. It suits products that use colour coding to differentiate strengths. Where the closure itself must carry intrinsic tamper evidence, specify the button type instead. Match the seal to a vial finish and stopper of the same nominal diameter; vial necks follow ISO 8362-1. Browse comparable closures on the by-size index.

Forms of supply and ordering

The seal ships Regular (non-sterile), Ready-to-Use (RTU: assembled in the ISO Class 8 cleanroom, double-lacquered aluminium, washed to control particulates, then gamma irradiated or ETO sterilized, supplied double-bagged for aseptic areas) and Ready-to-Sterilize (RTS). Shelf life is 3.5 years before capping for non-irradiated seals (plus 5 years after capping) and 2 years before capping for RTU.

To order, contact Autofits with your size, the grooved bridge design, finish, colour reference and required form of supply. Minimum order quantities and lead times are available on request.

Frequently asked questions

What does the groove do on a FlipTop Optima seal?

The groove is a forming feature on the crown. It helps the aluminium shell seat and crimp consistently on the vial finish, and it supports a clean, predictable release of the flip button at point of use. It does not change the sealing principle or the tamper behaviour, which are the same as the standard bridge design.

How many bridges does the bridge design have?

Bridge count is matched to the seal diameter: six tapered bridges at 13 and 20 mm, eight at 28 mm and twelve at 32 mm. Matching the count to the diameter keeps the opening force controlled as the crown gets larger.

What is the opening force of the bridge design?

Maximum opening force is 35 N at 20 mm, 35 N at 28 mm and 65 N at 32 mm. Opening force varies with the number of bridges in the design.

What sizes is the with-groove bridge design available in?

The spec basis on this page is the with-groove drawings for 20, 28 and 32 mm. The bridge design also runs at 13 mm. Total seal height runs from 9.02 mm at 20 mm to 15.50 mm at 32 mm.

How is it different from the button and flower designs?

Bridge, Button and Flower are three top patterns within the same Optima family. The Bridge design uses a ring of tapered bridges under the flip button. The Button design adds intrinsic tamper evidence through a 12-stem flower formed under the button disc, and the Flower design uses a flower top pattern. All share the same AA8011 shell, epoxy lacquer and polypropylene button.

Is the grooved bridge type 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: 2026-07-06. 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.*