FSM4JSMA is a surface-mount tactile switch from the FSMJSMA Series, featuring a 6 mm × 6 mm square footprint designed for compact PCB integration. The switch is constructed with copper alloy silver-plated contacts, a PPS case and actuator button, and a steel tin-plated cover, providing reliable electrical performance with a contact rating of 50 mA at 12 VDC. Key performance characteristics include an initial contact resistance of 100 milliohms maximum, insulation resistance of 100 megohms minimum at 100 VDC, and dielectric strength of 500 VAC for 1 minute. The switch offers an actuator travel of 0.010 inches (0.254 mm) with selectable actuation force options and supports up to 100,000 operating cycles. Operating temperature range is -20°C to +85°C, with solder heat resistance rated for IR soldering per EIA-364-56 Procedure 5 Level 3 at 260°C, making it suitable for automated assembly and consumer electronics applications.