Sealed edges Cleanroom Class 10 (ISO Class 4) 100% Polyester Pre-saturated in 70% IPA/30% DI Water FREE-SAT ULTIMATE 70™ pre-saturated wipers are made of 100% polyester. These wipes have heat sealed edges. A laser beam cuts and melts each fiber along the edges, eliminating the chance of particle emission. These wipes are vacuum sealed in tough, alcohol resistant nylon bags providing a longer shelf life. (480 per CS ) Learn More