Block is stainless steel, gas port is about .145 but its adjustable so it doesn't really matter. #10-32 set screws 1/2" apart on underside. Also #10 set screws for the gas adjustment. It doesnt look "exactly" like the one in the pic, its missing that sexy radius on the corners and the hole for the tube is drilled through. I will post actual pics later if you want. I only have the block you need to get your own gas tube. The only place I could find a straight gas tube was Precision reflex