Lenox Snap-Back 3/8 in. x 7-1/2 in. L Steel Drill Bit Arbor 1 pc.

These arbors work well and make changing hole saws easy. The problem I see as a non-professional DIY homeowner is that they're not intuitive to use and, inexplicably, there are no instructions for use in the packaging- NONE. This lack of instructions may be the root cause of the dissatisfaction expressed in some reviews. The review writers may not be using the tool as designed. So here's how to use them: Snap the silver collar back to extend the threaded part of the arbor. Screw the arbor into the threaded center hole on the back side of the hole saw until the pins on the silver collar bottom out. Then back off the threads slightly until the pins line up with the small holes adjacent to the center threaded hole and snap it in place. Done. To remove, snap the collar back to pull the pins out of the holes and unscrew.