Damn. TWO NiteRiders? You trying to land aircraft or something?

The adapter block is milled aluminum, it was Amazon Prime...made by some no-name in China and probably violate a dozen patents...but does the trick. Like most products listed on Amazon they list is Prime and cheap (I paid $15USD for it) until someone buys one, then they remove Prime and jack the cost up:

Robot Check

That alu block takes the NR slide that unscrews off the standard NR mount on one end....then it becomes a GoPro that can plunk right into a standard K-Edge GoPro/Garmin mount. Keeps the light pointed exactly where I set it and it doesn't move ever, unlike most handlebar mounts...and even better it doesn't take up handlebar space that way.