Review on AUTO TOOLHOME Self-Centering Doweling Jig with Step Drill Guide Bushings Set - Simplified Wood Dowel Jig for Efficient Woodworking Joint Creation by Brian Wolf

Great thing! The coolest jig from China I've bought. In typical Chinese style, instead of using a locking ring to attach a threaded collar, they simply secure the collar with a pair of threaded fasteners and washers. It doesn't affect performance right out of the box. Regardless, this thing works great. Does exactly what I need. It comes with a variety of threaded bushings for different applications. If you have access to a Bridgeport router you can easily modify it and add a locking ring yourself, but you don't have one, it works as is. Give it a try, I don't think you will be disappointed.