The barrel nut is included the wrench is notand can be found here:
https://www.opticsplanet.com/geissele-barrel-nut-wrench-02-243.html
The handguard will come with all of the hardware to install the rail, but will no longer include the barrel nut wrench as of last year and per Geissele, "Effective 3/31/20 Geissele will no longer include the gas blocks with the rails." The barrel nut wrench and gas block can be found here:
https://www.opticsplanet.com/geissele-barrel-nut-wrench-02-243.html
https://www.opticsplanet.com/geissele-super-gas-block-stainless-steel-05-231.html
https://www.opticsplanet.com/geissele-super-gas-block-black-nitride-coated-05-231n.html
The Geissele Super Gas Block is not adjustable, but please be aware that per Geissele, "Effective 3/31/20 Geissele will no longer include the gas blocks with the rails."
The gas block is made of 17-4 precipitation hardening stainless steel, but please be aware that per Geissele, "Effective 3/31/20 Geissele will no longer include the gas blocks with the rails."