One of the June 2009 releases from X-Fire/PDI-Japan... "For Tokyo Marui HI-CAPA 5.1. Made of CS (carbon steel) all machined. The flange & shaft are welded by YAG lazer. It's processed black oxide. Marui's Original guide has 3 problems which are 'hole', 'line on the shaft' and 'peeling off', PDI's guide are stainless steel all machined, so not peeled, no hole and no line. Really good surface.  Marui's original guide is longer than PDI, so it's protuded somewhat. PDI makes it similar to that 'STI International Model of IPSC', so it's not protuded."