The 204-121ST is a surface mount multi-functional DIP switch featuring single-pole double-throw (SPDT) circuitry with one switch position, designed for compact electronic applications. The switch incorporates an integral terminal and contact molded into a thermoset base with electrostatic discharge protection rated to 22 kV, and features optimized gold-plated contact design with a dimple wiping interface for long-term corrosion resistance. Key specifications include a maximum coplanarity of 0.1 mm, contact resistance of 50 milliohms maximum, insulation resistance of 100 megohms at end of life, and an actuation life of 5,000 cycles at 50 mA and 24 VDC. The switch operates over a temperature range of -40°C to +85°C and features enclosed actuators that shield contacts from foreign particles, with optional top tape seal for board spray washing. This component is ideal for applications requiring reliable switching in space-constrained environments such as consumer electronics, industrial control systems, and telecommunications equipment.