Compatible with: Pneumatic Tools NR83A & NR83A2 (A3 & A5) Hook nail gun on a rafter, joist, trusses, etc. Quick and simple install Specifications: Aluminum The Superior Parts GH3, 'U' Shaped Nail Gun Rafter Hook Compatible with Hitachi NR83A & NR83A2. The Gun Hook easily installs on your NR83A or NR83A2 air inlet cap. When installed, the forks on the Gun Hook are positioned to hook on a rafter, joist, trusses etc. Built to last made with premium grade Aluminum and tested for long lasting durability.