XRAY Active Diff portions are CNC-machined from really tough steel, while having extremely precisely-machined "V" ramp grooves with 90ð angle for easy engagement/disengagement. The part is hardened to make sure long life and durability. The portions are laser etched with "90°" for simple and easy instant recognition. Pair of 2. The 90° sections provide a very good stability of performance between on- and off-power. On-power the diff becomes difficult after a quick delay. Off-power the diff becomes free after an instant delay. To be used on medium traction songs. Active Differential portions are available in three different options: #352123 - 60° #352125 - 90° #352127 - 120° Active Differential parts fit: #325100 - Active Differential for XB2/XT2/SCX #365100 - Active Differential for XB4/XT4 Font/Rear #365101 - Active Differential for XB4/XT4 Center