I bought the Mako titanium knife to go with my Hydros, its annoying because I didn't know you needed to buy the multi mount along with the knife if you want to mount to your BCD and then I found when fitting if you have knife handle facing front which makes most sense it sticks out too far fand I'm constantly knocking my arm against it so in the end had to mount with handle facing the back to avoid that issue, I guess for how often I will need to use it its ok but I did feel it was a bit of a design flaw.