The 53257 is a radiation tolerant, DC solid-state relay (SSR) designed for military and space applications. This light weight device is resistant to damage from severe shock and vibration, and is immune to contact related problems inherent in electro-mechanical relays. The 53257 SSR is enclosed in a hermetic metal package to ensure reliability in harsh environments. Effective isolation of 1000 VDC between control and load circuits is achieved through the use of optical coupling.