This nitrogen fill tool is needed to check or refill the nitrogen charge when servicing ICON 2.0 and 2.5 smooth body shocks, as well as 2.5 non-reservoir coil over shocks. On these shocks we use an in house CNC machined charge port which has a low profile design for clearance. The ICON nitrogen fill tool is required to puncture a rubber plug in the charge port, allowing nitrogen into the shock through the hypodermic needle.