This is a Swain Original. When I drilled holes in my bench to use dog hole accessories, I wanted to make my own accessories. I started by using wooden dowels and drilling holes in them. Well, that got old real fast. So, I designed my own. These dog hole dogs are meant for 20mm inch holes. They have a 1/4 inch hole for either a screw it 1/4-20 bolt. *This product is printed out of PLA. Do not leave it outside or expose it to temperatures above 115 degrees Fahrenheit.