These lightweight inserts are sized to fit most soft panniers (including our WPA133 TrailMax Canvas Pack Panniers, WPA135 Canvas & Leather Pack Panniers, WPA136 TrailMax Iron Cloth Pack Panniers and WPA140 TrailMax Saddle Pannier, All Found On Amazon). They provide protection for packed goods and give panniers shape for ease of packing. These nearly indestructible pannier liners are made of a durable but flexible polymer plastic. The thickness is approximately 3/16" on the sides and approximately 1/4" at the bottom. Material is also easily cleaned with mild soap and warm water. Rest assured, these are made in America, and have the expected quality to match. Each set is hand inspected, and all sharp edges are eliminated to ensure that they do not interfere with the integrity of your panniers.