This may appeal to some who don't like having to cut, trim, and mount their frag plugs.
Apparently you don't have to drill either, just find a small crevice and twist them in. It looks to be a nice small profile also so the frag has a better chance of seamlessly covering the plug and rock.
Found the info here:
http://reefbuilders.com/2012/01/17/reeftap-frag-plug/