These new spindle arms help fine-tune corner entry, middle, and exit steering response to your liking. Steering Response: More balanced entry, mid, exit steering. When Recommended: Medium grip, mid-size tracks. Ackerman: Less than TKR9047A Vehicle Compatibility TKR9047A - Spindle Arms (EB/NB/ET/NT48, requires TKR9041X, Type A) is not included with any kit. This can be used with the EB48 2.0, ET48 2.0 and NB48 2.0 vehicles and should be a direct replacement for the stock part or used as a new feature. Please use the instruction manual for the kit(s) listed to verify compatibility and no additional items are necessary before purchasing.