56-959 CTEK MUS 4.3 Test&Charge Charger. The CTEK MUS 4.3 Test&Chrage Corvette Battery Charger combines a micro-processor controlled battery charger with a battery and alternator test function. Designed specifically for batteries from 1.2Ah all the way up to 110Ah. The 4.3 features a patented automatic desulphation program, a re-conditioning program that will even restore stratified batteries. The patented Float and Pulse charging makes this the ideal charger for long term battery maintenance as well as diagnostic insite.