The Ultra Knurled Insert is the best way to install our HZ or ST Wine Pegs. The Ultra Insert allows you to seamlessly install our HZ or ST wine pegs into wooden panels while providing extreme consistency while installing the pegs at a straight angle. If you plan on installing our HZ or ST Wine Pegs without the Ultra Insert accessory, you must be able to access the back of the panel storage system to secure the M6/M8/10 threaded Wine Peg.