The only two-wire, per-assembled starting components Hard Start Device on the market that uses a high-quality Mechanical Potential Relay in a unique design! Absolutely no use of circuit boards, timers or PTCR devices! KS-1 (3.5-5 ton max. torque) both work with single-phase 208V, 230V and 265V A/C Refrigeration and Heat Pump Compressors.Hard start devices extend the life of compressors considerably by bringing them up to full speed more quickly and efficiently. I have 2 new in package, these sell for $125 ea all take $50 ea.you cannot buy these in any store. for home or business use