Part - SP-35 Needle Guide

This is the old style of chucking guide without the back lever.

Old style
If your needle chucking guide has a groove cut into the cylindrical barrel (as indicated by the red arrow in the image below) and your airbrush body has a screw underneath to hold the chucking guide in place, then you need this old style of needle chucking guide as a replacement. The old-style auxiliary back lever is a separate item

New style
If your needle chucking guide has a cylindrical barrel with no groove and your airbrush body has no screw underneath to hold the needle chucking guide in place, then you need the new style of needle chucking guide, which comes assembled with the auxiliary back lever attached.