The tifosi tyrant 20 sunglasses have a frame which is made from grilamid tr90 a homopolyamide nylon which is flexible and durable and features a hydrophilic rubber on the arms and nose pads providing you with a custom and more comfortable fit as the nose and ear pads are easily adjustable in order to limit slippage the hydrophilic rubber used on these tifosi cycling sunglasses increase their grip the more you sweat for a precise and none slip fit to prevent your sunglasses fogging up and to