tankmate: No. It's a Clippard part.
clawlan: Attach the regulator to the cylinder. Be sure to use a wrench and get manly on it. You can't break it. Attach CO2 tubing to the regulator (note that some regulators have a built-in bubble counter). Attach tubing to check valve. Attach check valve to bubble counter. Attach second check valve to bubble counter. Attach tubing from second check valve to diffusion method. Plug solenoid into controller. Set bubble rate using needle valve.
Why are there not more complete sets? Because most people selling CO2 equipment figure that you can do the research and know what to buy and don't want to put a box of crap together and field the support calls.
A reactor is normally mounted outside the tank and a diffuser is mounted in the tank. They both have the same function, to get CO2 into the water column. So go with one or the other. If you don't have a canister filter you can save yourself a lot of work and plumbing by just using a diffuser.