Pack types guide

Pack types explained: punnets, clamshells, trays and more

Rigid plastic packs are all made by thermoforming sheet, but each closes and protects in its own way. This guide explains the main types (punnets, clamshells, heat-seal punnets, flowpacks, hinged and tamper-evident containers, MAP trays and blisters) and when to use each.

Written and reviewed by the AVI technical team, from AVI Global Plast's own catalogue and production data · Updated

At a glance

Type How it closes Best for
Clamshell Hinged lid snaps shut Berries, grapes, tomatoes
Heat-seal punnet Film sealed to the rim Automated lines, tamper-evident, MAP
Flowpack tray Wrapped in film Lowest material use
Overwrap tray Wrapped in film with the product Mushrooms, vegetables
Hinged-lid container Hinged lid Salads, bakery, deli, snacks
Tamper-evident clamshell Locks, tear strip to open Ready-to-eat food, delivery
MAP tray Barrier film sealed after gas flush Meat, poultry, seafood
Egg tray Open cells Eggs
Blister Sealed to foil or card Medicines, retail goods

How to choose

Start from the product and your packing line: hand-packing favours clamshells; a tray sealer opens up heat-seal punnets; a flow-wrap line suits flowpacks. Then match the size to your fill weight and market.

One example of each type

PackTypeSize (L × W × H)Empty weightHoldsPer carton
PNG 250 / 75 Hinged lid 128 × 94 × 75 mm 9 g 250 g 1,225
A-30 / 45 Flat lid heat-sealed to base 145 × 120 × 45 mm 7 g 250 g, 250 g heat-seal 2,100
FLW 180 120 / 60 Wrapped on a flow-wrapping line 184 × 117 × 60 mm 9 g 500 g flowpack 1,420
TB 750 / 850 Hinged lid container 188 × 145 × 60 mm 24 g — 610
TE 750 / 24oz Hinged clamshell with tamper-evident closure 189 × 145 × 60 mm 34 g — 310
RTE 104 140/40 Modified-atmosphere-packaging tray 140 × 104 × 42 mm 10 g — —
12 EGG TRAY Open tray 196 × 149 × 65 mm 26 g — 600
TBT 175 125 / 43 Overwrapped tray 175 × 125 × 43 mm 9.5 g — 1,800

All packs are rPET. Figures from AVI's catalogue; tolerances and fill depend on the product, so samples are the final check. See the full catalogue.

AVI products

Terms in this guide

Blister pack
A formed plastic cavity sealed to a backing of foil (medicines) or printed card (retail goods).
Clamshell
A one-piece pack whose lid is joined to the base by a hinge, so it closes on itself and can be reopened.
Flowpack
An open tray wrapped in film on a horizontal flow-wrapping machine, a light alternative to a lidded pack.
Heat-seal punnet
An open tray closed by heat-sealing a film lid to its rim. Tamper-evident and light, but it needs a tray sealer.
Hinged-lid container
A one-piece tray and lid joined by a hinge, used for salads, bakery, deli and snacks.
MAP (modified atmosphere packaging)
Packing food in a sealed tray where the air is replaced with a protective gas mix, which slows spoilage.
Nesting
Stacking empty packs inside one another. Packs that nest deeply fit more to a carton and a container.
Overwrap tray
An open tray that is wrapped in film with the product, common for mushrooms and vegetables.
Punnet
A small retail pack for soft fruit and vegetables such as berries, grapes and cherry tomatoes.
Tamper-evident
Shows clearly if a pack has been opened, for example a strip that tears off on first opening.
Thermoforming
Heating plastic sheet until soft, forming it over a mould with vacuum or air pressure, then trimming: how punnets, trays and blisters are made.

The full A–Z glossary

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