Designed with the same waterproof performance found in HydroLite® sacks Outdoor Research Hydroseal Pack Sacks™ feature a highly durable Antron nylon fabric that enhances overall durability making these sacks excellent for rolling across abrasive surfaces like open rock faces while climbing. Hydroseal Pack Sacks™ even feature external daisy chains for easy clip-in attachments. Granted you don't want to throw out your durable climbing haul bags and replace them with these lighter sacks but the extra grams of protection are excellent if you can't hassle with frayed or potentially fragile storage sacks.