Bobbo if you've seen a cheese grater battery load tester you'd remenber it. They are rectangular punched full of round holes with a pair of cables and clamps. Great for lawn and garden tractor batteies, with a 100 amp test load but utterly useless for anything bigger. An impedance battery tester looks like a multimeter but has cables and clamps. A vendor that uses a cheese grater is to be avoided. As a matter of fact a battery vendor who does not utilize an adjustable carbon pile tester (like yours) and a Freas hydrometer should be avoided. People who get paid real money but deliver Amateur Hour service are a real pitfall.