The 39-101 is a single-pole, single-throw (SPST) pushbutton limit switch featuring a red over-travel button and NO (normally open) contact configuration. It has solder lug terminations and is designed with a tin zinc brass bushing and mounting nut. The switch's body is made from thermoset plastic, with gold-plated over nickel commercial bronze terminals, a tinned music wire spring, and gold-plated contacts for reliable electrical performance. Operating parameters include a maximum contact resistance of 25 micro-ohms on a new switch and a minimum insulation resistance of 1000 megaohms, with an operating temperature range from -40°C to 85°C. Suitable for industrial applications.