Drop in T-Nut is very useful because they need not to be placed from the end of the V-slot (like the conventional T-nut), but they can be easily placed any where in the V-slot. This means that you can use them even after mounting items at the ends of the V-slot

T-slot Nuts are inserted into the aluminium profile grooves to connect one profile to another or to secure components to profile structures, allowing a clamping force for the screw in the groove.