hilti gx100 gas Canisters gc11 canister are hard to find so use the gc22 I hope this help you out - YouTube
GX-IE Gas-actuated insulation nailer - Gas actuated direct fastening tools - Hilti USA
Gas Cylinder (GC11) compatible with Hilti GX100 Nail Gun (Adapter not included, please use it from the original cylinders) : Amazon.se: Tools & Home Improvement