Tecmate OptiMATE TEST &ndash; Cranking & Alternator, TS-121, 12V tester for battery state of charge, cranking performance and vehicle charging system. BATTERY TESTER - The ultimate pocket tester for on-vehicle battery performance & alternator voltage testing that every service technician or gear head should have. ACCURATE - Microprocessor accuracy; Fully sealed. MODEL - TS-121 Length: 40 / 100cm battery clip set. INDUSTRY STANDARD - Industry standard SAE 2-pin connector. EASY TO USE - Easy to follow instructions on rear panel of the tester.