Wilden EZ-Install TPE diaphragms have a convoluted shape that allows installation without inverting them. Available in Santoprene, Hytrel, polyurethane and Geolast options, the diaphragms are used in Wilden 1 1/2-, 2-, 3- and 4-in. Original and Advanced Series air-operated double-diaphragm pumps; they are compatible with existing hardware. 

Wilden Pump and Engineering; www.wildenpump.com