This is a drop-in anchor setting tool for installing 3/8" drop-in anchors. It has a pin length of 33/64". The sheet identifies it as a Cully tool from Minerallac.

This is an anchor setting tool used to install 1/4 in shallow embedment "Mini" drop in anchors. It is a setting tool for concrete and masonry anchor applications. The page lists it as an active product with packaging in a bag and a unit of measure of each.

Minerallac 3/8" SDS Stop Bit for Mini Undercut Anchor.