Be sure to ask the seller how many hours are on the drum heads. If the seller does not know, advise person to power unit to on and press set locate and stop. This will briefly display the total hours. Minutes are not displayed when set locate and stop are pressed. Be suspicious of claims stating only 2 hrs 43 minutes. This is more likely to be 243 hours. That's a big difference when the claim is 20 hours and 46 minutes which would actually be 2,046 hours.