Polyolefins are used for blown film and heatshrink electrical insulation sleeves for crimped wire terminals, as well as rash guards or under garments for wetsuits. Polyolefin elastomer POE is used as a main ingredient in the molded flexible foam technology such as in the fabrication of self skinned footwear (for example, Crocs shoes), seat cushions, arm rests, spa pillows, etc. Hydrogenated polyalphaolefin (PAO) is used as a radar coolant. Head makes polyolefin tennis racket strings. Polyolefin is also used in pharmaceutical and medical industry for HEPA filter certification—a PAO aerosol is passed through the filters and the air that exits is measured with an aerosol detector.[10] Elastolefin is a fiber used in fabrics.[11]