The BIOLOID Compatible Metal F4 Bracket is a aluminum replacement for the standard BIOLOID F4 bracket. 4 tapped holes on the sides of the frame make it easy to mount cable holders and 3D frames. This is the same frame as used in the HR-OS1
Two F6 Brackets, One F7 Bracket, and Two AX-Series Servos (AX-12A, or AX-18A) are required to create a dual joint.
This product is just the single metal bracket. This frame requires a Hub & Washer, an M3 * 10 bolt, and 4 M2*6 bolts (both bolts can be found in the Nut and Bolt Variety Pack). The AX-12A comes with this hardware, but the AX-18 does not.