"TEC-HRO hook" is the hook from our butt-plate "TEC-HRO fusion" and have a lot of advantages against other hooks. So for example the hook can be offset sideways..."TEC-HRO hook" will also fit on other butt-plates (for example MEC free position...) and so you have the possiblity to use a part of the advantages from "TEC-HRO fusion" also on other butt-plates!!We advise to take also the rod from "TEC-HRO" for your hook because this one is knurled on the side where the hook will be mounted and so it holds much better!!