Pressure Gauge with Nut 0 to 35 PSI

Pressure gauge with nut and washer 0 to 30 PSI

Scale 0 to 35 Psi. You can drill a small hole in your cap or the top plate of your cornelius keg and fit this easily.

A plastic pressure barrel usually runs at about 7 psi , the Cornelius kegs will take a lot more!