For smaller applications the DUO Build System also comes in a 15mm x 15mm square extrusion. The 15mm profile of the 15mm Extrusion has slots on on all four sides that accept standard M3 hardware. Rather than using a T-nut, which is more expensive, slide a M3 hex head screw along the slot and adjust brackets and other build materials as needed.

This product is a 4-pack of 420mm pieces of extrusion, an appropriate length to fit within the frame perimeter on your FTC robot without extra cutting.