Calandra Racing Concepts now has 2.5 mm hardened diff balls available for the full line of CRC spur gears. Unlike the .093"(3/32) balls, these 2.5 mm balls pop in the gear's ball sockets and stay put making diff building a lot easier. The 16-ball design of CRC's gears provide improved diff performance over the 12-ball designs of the competition's spur gears. The smaller 2.5mm size ball is much lighter than the larger 1/8" ball used in other gears.