Our postal locks have been approved by the Manufacturers of USPS Postal Equipment. ESP offers 4 different multi cam packages to ensure lock compatibility in the field. We offer standard lengths of .656 (ESP). The 656 can be ordered for outdoor (Dust Shuttered) or indoor (Non-Dust Shuttered) applications. Furnished with 5 cams, 2 clips and 2 slots, ESP accommodates varied door thicknesses.