XRAY Active Diff portions are CNC-machined from in fact tough steel, whilst having acutely precisely-machined "V" ramp grooves with 90ð angle for easy engagement/disengagement. The component is hardened to make sure longevity and durability. The portions are laser etched with "90°" for easy and simple instant recognition. Few 2. The 90° sections offer a very good safety of performance between on- and off-power. On-power the diff becomes quite difficult after an easy hold off. Off-power the diff becomes free after a rapid delay. To be applied to medium traction tracks. Active Differential portions can be bought three various options: #352123 - 60° #352125 - 90° #352127 - 120° Active Differential components fit: #325100 - Active Differential for XB2/XT2/SCX #365100 - Active Differential for XB4/XT4 Font/Rear #365101 - Active Differential for XB4/XT4 Center