This is a replacement pack of four Arrma 4x9x12.5mm Balls, intended for use with the 8s-BLX Kraton kit.
 
Features:
Precision manufactured from strong steel for maximum crash resistance and long-lasting durability
9mm diameter pivot ball - 4mm through-hole
12.5mm overall length
Includes:
(4) Ball (4x9x12.5mm)