The Apeks Blanking Plug Set is a set of replacement 1st stage plugs to seal unused ports. A pair of low pressure ports and a high pressure port with O-Rings will fit most 1st stages and all you need to screw them in is a 5mm allen key.
SPECIFICATIONS
x1 - 3/8"UNF LP plug
x1 - 1/2"UNF LP plug
x1 - 7/16"UNF HP plug