Rugged Pushbutton switch , N.O. (normally open), rear mount, 5/8-24 threaded bushing, black button, clear anodized case, dust tight. Makes and breaks every time! Less than 25mΩ contact resistance because the OTTO design features inherent rocking action that breaks welds and wipes contacts clean. The P3 is the commercial version of the P1 Pushbutton switch, offering vastly improved life under extreme conditions found in some industrial environments. The pushbutton is sealed by a silicone boot operating on our patented “rolling sleeve,” providing longer life and smoother operation over a wide temperature range.