This 6 and 12 Volt with true 100 Amp load battery tester works with conventional and maintenance free lead acid batteries. The unit is completely portable; outside power in not required. Tests can be completed in 10 to 15 seconds. Features: Heavy duty copper played clamps. Internal load unit with 100 amp load capacity. UL listed load safety switch to prevent arcing. Heavy duty steel case. Convenient insulated carrying handle. Complete with fully illustrated instructions. Load Testing a Battery: Turn engine and all electrical accessories off. Connect BLACK clamp to battery NEGATIVE. Connect RED clamp to battery POSITIVE. Hold Load switch on for 10 seconds (15 seconds max). Read meter with load still on and refer to battery analysis table.