Totally solid state, our DST-5 is just right for all permanent split capacitor (PSC) compressors from 1/2 to 10 H.P. It can be used on units that operate on 120 through 288 Volts. The DST-6 offers a larger capacitor for severely hard-to-start compressors. The DST-6 can be used on all PSC single phase compressors from 1-1/2 to 10 H.P. A unique combination of relay and safety timer. The capacitor is automatically disconnected in 0.5 seconds if the compressor fails to start