auxiliary switch, 1 NO+1 NC for miniature circuit breaker 5SL, 5SY, 5SP Incorporated switch 5TL1, RCBO 5SU1, FI 5SV (for 5SU1 handle coupler 5ST3805-1 is required) auxiliary switches SENTRON 5ST3 as additional components for residual current devices and miniature circuit breakers.These additional components can be mounted universally. They are easy and convenient to install and connect. Thanks to the standard touch protection, safety is reliably ensured during installation.Optimized technology for your safety - only from Siemens.