This is the Align 450DFC Linkage Rod Set. This Linkage Rod Set is compatible with the Align T-Rex 450 Pro V2 T-Rex 450 Sport V2 T-Rex 450 Sport and T-Rex 450 Pro. Includes: 450DFC Linkage rod A x 4 ( M1.6 x 12mm ) 450DFC Ball link x 4