Disclaimer: I'm using this for a non-Garmin radar, not the Blade light.
My primary desire was for a mount that didn't have a hinge or fixing bolt sticking out on the side as those mounts rub my leg, and to be secure enough that it won't twist on the seatpost if it gets bumped. This fits that need quite well. I'm using it on a 27.2mm seatpost and it's quite secure. There are 2 things to note if you want a happy experience:
1. The insert for a 27.2mm post and the mount have very tight tolerances. I found I needed to test fit the insert to the mount before putting it on the seatpost as it only would fit in one orientation. Once that snapped fully into place, I could then take the two pieces apart and put them on the seatpost using the orientation that worked.
2. The mounting bolt wasn't long enough to grab the threaded insert on the other half of the mount. It missed by a very tiny bit. I used channellock pliers to lightly squeeze the mount just a wee bit and the bolt mated with the insert and screwed in the rest of the way without any trouble. I'm confident my radar isn't going to move at all.
For my purposes, I had to use my own quarter-turn to action cam mount as my radar was a quarter turn rotated from the Garmin standard. That's absolutely no fault of the light mount, but I want to be clear to others that the provided Garmin insert can't be rotated if that's something you need.
