FEGG | Ethical, Unbreakable & Foldable Silicone Tumblers - Aubergine & Donkey Colours These reusable stylish tumblers by Porter Green are made using FDA-approved food-grade silicone, beautifully designed to be light, portable and unbreakable - perfect for travelling and everyday living. Ethical and sustainable, these tumblers are great to drink from, completely odourless and won't retain flavours!