Up for sale is a set of used German Mahle AAZ pistons in excellent used condition. I have disassembled quite a few IDI engines and these are the best used set of pistons I've seen. They are standard size. There is a very slight exhaust valve impression on the crown of each of them. There are also very slight vertical lines on the skirt of a couple of them. The cost for the set of four is $75 shipped in the continental US for the set. Price is firm. I'd ship elsewhere, but the cost for shipping would be more.