Swimline Ripstopper Winter Cover is the ultimate winter cover. It is durable, dependable and built to last. If your cover gets a hole or a puncture, no need to worry, this cover will not rip or tear. Constructed of woven polyethylene fabric, the pool cover is time tested and is sure to last a few years. This tightly woven solid cover material is made from a super-strong polyethylene with an 12 x 12 filament scrim to resist the harsh winter weather.