4 x 3 ICE GEL SHEET FREEZE PACK WATER PICNIC POSTAGE CHILLED FROZEN FOOD PERISH

Tip: When freezing more than one sheet, place plastic film or waxed paper between sheets or place inside a plastic bag to stop them sticking together. Soak the sheets for 30-60 minutes in fresh water (warm water works better), ideally and works best overnight.

eBay