One size for all compressors from 1/12 HP through 1/2 HP. For both domestic and commercial refrigerators and freezers. The installation of a start capacitor in series with the start winding in order to overcome starting problems was common practice. Then manufacturers started using push-on relays which left no practical way to install a start capacitor. Now this problem has been solved with a New Combination Relay and Start Capacitor 'The Big Relay'.