They are unfinished repair liners. Cummins dealers sell them and so does Felpro. They are about $40 a piece new so $60 each from China sounds like less than a good deal.
Most Recon Cummins motors are ring/bearing slapped, really worn ones are bored oversize and when they come back worn with a .040" overbore they are sleeved back to standard and sent out again. The repair sleeves are also used to fix one bad hole, such as a cracked bore or deep gouge from a wrist pin.
The repair sleeves are alot of work to install, especially cutting the sleeve even with the deck when trying to avoid decking the block.
