Linkage ball H50094T-1 for RC helicopter Align T-Rex 500. Included:linkage ball A (M2.5x3.5) x 4 (Ø4.75x8.18mm),linkage ball B (M2.5x3) x 2 (Ø4.75x9.77mm),linkage ball D (M3x3.5) x 2 (Ø4.75x17.5mm).