The M-4759-2 is a 0-200 PSI liquid filled pressure gauge, 2 1/2" glass face diameter. This gauge is a flange mount with 3 - 1/8" holes on the flange for mounting and an 1/4" NPT threaded connection on the back. (Image shown is a 0-200 PSI Liquid Filled Pressure Gauge, however it's not a M-4759-2 gauge.)