As the title says, its a Holder for a UV flashlight based on the Multiboard system, but it also works with anything that has a diameter of 55mm. It uses a modified bolt that is a bit shorter then the official short bolt. I didn't make the original bolt, you can download it and other base multiboard parts at https://www.multiboard.io. supports shouldn't be needed. 

Thanks Johnathan at Keep Making! for creating the Multiboard system.