When you need to compress volume without significantly adding weight, the Sea to Summit Ultra-Sil Compression Sack - 35L is an excellent solution. Made from a water-resistant, bluesign® approved Ultra-Sil 30D nylon fabric with Non-PFC DWR this compression sack is far tougher than its weight would suggest. Ideal for use inside your pack or travel bag when you need to compress clothing or bulky soft items to allow space for other essentials or fun holiday items.