This is the RTI Model Vastus System
The Vastus System from 9Toes Design is a lightweight thigh band mod that will work with any drop-leg system sporting a G-Code RTI hole pattern. The system keeps your thigh strap dropped below the holster and belt mount for a more comfortable fit that prevents the strap from riding up the leg. The Vastus System manages the thigh band to stay perpendicular to the leg. No one wants their bits in a bunch. The Vastus is built with some of the newest and strongest materials on the market, and is high-frequency welded for the strongest bond possible. The Vastus System is reversible, black on one side, and coyote tan on the other.