ross custom pistons for turbo application.the pistons are 83.5mm or 3.287".the compression height is 1.135", the top ring-1mm, sec. ring-1.2mm, oil ring-2.8mm.each piston weighs 310 grams.pistons are in excellent condition, almost brand new.pistons were designed with a thicker ring land and deeper valve pockets.I payed $600.asking $300 obo. pistons are for b-series