My rack has a tab on the back with a single hole in it. I drilled a small hole in the back casing of my Superflash (there's a small recess in the back that works perfect). Then I just screwed it to the tab and used a small o-ring to keep the water out. It's been working just fine that way for 3+ years now. Despite people telling me that I had "comprmised the integrity" of my light. Total cost was a screw, a nut, and an o-ring. All of which I had lying around.