Two large air compressor heads, the gray one us a Quincy and I believe the red one may be a champion, they both spin freely, have compression and zero play in the main shaft. I was going to build a large unit for my garage but too many projects and not enough time have gotten in the way, they would be good replacements or backups for someone with a system that uses these large heads. They are very heavy, I'm sure in excess of 150 lbs each or there abouts. Just trying to free up some space and make room for other things I'm not going to use. I would like 100.00 for the pair.