Just bought one of these on clearance at WalMart last night. Deltran Battery Tester PN 026-0020 (old fashioned kind that uses a resistance coil to load the battery). Caveman simple,effective, and quick. Probably super reliable. Just cracked open the box this evening and went around the homestead checking out 6 batteries in the various cars, tractors, etc. Posting this here as i have been checking out about half a dozen local Wal-Marts and noticed that they have all significantly ramped up clearance all over their stores of what I perceive to be slower selling items. Several items in the battery jump starter, tester, etc area were on clearance. I recalled using this type of battery tester when i worked in an auto parts store. For $16.50 (half the regular price) I got to relive some old memories. Cheers!