Refer to the AR-A/AR-B/AR-D series catalog excerpt, which has been reproduced below.
The part number of the standard AR20 to AR60 round type pressure gauge is “G36-10-01,” or “G46-10-01”(for the R thread type).
For example, the part number of the AR30-03BG-A pressure gauge is “G36-10-01.”

Refer to the AR-A/AR-B/AR-D series catalog excerpt, which has been reproduced below.
The part numbers of standard AR20 to AR60 round type pressure gauges are “G36-10-01” and “G46-10-01”(for the R thread type).
For example, the part number of the AR30-03BG-A pressure gauge is “G36-10-01.”

Size: 1/8, Reverse Flow: Regulator, Standard, Thread: NPT, Port Size: 1/4, Accessory: Panel Mount w/Set Nut, Option 1: None, Option 2: Name Plate & Pressure Gauge in Imperial Units, PSI, °F

Body Size: 20, Backflow: w/o Backflow Function, Thread: NPT, Port Size: 1/4, Options: w/Set Nut, for Panel Mount, Set Pressure: 0.02 to 0.2 MPa Setting, Exhaust Mechanism: Relieving Type, Flow Direction: Left to Right, Knob: Downward, Pressure Units: Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale

Body Size: 20, Backflow: w/o Backflow Function, Thread: NPT, Port Size: 1/4, Options: w/Set Nut, for Panel Mount, Set Pressure: 0.05 to 0.85 MPa Setting, Exhaust Mechanism: Non-relieving Type, Flow Direction: Left to Right, Knob: Downward, Pressure Units: Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale

Body Size: 20, Backflow: w/o Backflow Function, Thread: NPT, Port Size: 1/4, Options: w/Set Nut, for Panel Mount, Set Pressure: 0.05 to 0.85 MPa Setting, Exhaust Mechanism: Relieving Type, Flow Direction: Right to Left, Knob: Downward, Pressure Units: Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale

Body Size: 20, Backflow: w/o Backflow Function, Thread: NPT, Port Size: 1/4, Options: w/Set Nut, for Panel Mount, Set Pressure: 0.05 to 0.85 MPa Setting, Exhaust Mechanism: Relieving Type, Flow Direction: Left to Right, Knob: Upward, Pressure Units: Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale

Body Size: 20, Backflow: w/o Backflow Function, Thread: N (NPT), Port Size: 02 (1/4), Options: H (w/Set Nut, for Panel Mount), Set Pressure: 1 (0.02 to 0.2 MPa Setting), Exhaust Mechanism: Relieving Type, Flow Direction: Left to Right, Knob: Downward, Pressure Units: Z (Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale)

Body Size: 20, Backflow: w/o Backflow Function, Thread: N (NPT), Port Size: 02 (1/4), Options: H (w/Set Nut, for Panel Mount), Set Pressure: 0.05 to 0.85 MPa Setting, Exhaust Mechanism: N (Non-relieving Type), Flow Direction: Left to Right, Knob: Downward, Pressure Units: Z (Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale)

Body Size: 20, Backflow: w/o Backflow Function, Thread: N (NPT), Port Size: 02 (1/4), Options: H (w/Set Nut, for Panel Mount), Set Pressure: 0.05 to 0.85 MPa Setting, Exhaust Mechanism: Relieving Type, Flow Direction: R (Right to Left), Knob: Downward, Pressure Units: Z (Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale)

Body Size: 20, Backflow: w/o Backflow Function, Thread: N (NPT), Port Size: 02 (1/4), Options: H (w/Set Nut, for Panel Mount), Set Pressure: 0.05 to 0.85 MPa Setting, Exhaust Mechanism: Relieving Type, Flow Direction: Left to Right, Knob: Y (Upward), Pressure Units: Z (Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale)

Cost effective and clean looking, series AR regulators offer various pressure range settings to accommodate most applications. The locking adjustment knob prevents accidental setting changes. The modular design of the AR series connects with other SMC air preparation equipment.Modular type regulator, Optional embedded pressure gauge , Available with built-in backflow mechanism , Knob is

Body Size: 20, Backflow: w/o Backflow Function, Thread: N (NPT), Port Size: 02 (1/4), Options: H (w/Set Nut, for Panel Mount), Set Pressure: 1 (0.02 to 0.2 MPa Setting), Exhaust Mechanism: N (Non-relieving Type), Flow Direction: Left to Right, Knob: Downward, Pressure Units: Z (Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale)

Body Size: 20, Backflow: w/o Backflow Function, Thread: N (NPT), Port Size: 02 (1/4), Options: H (w/Set Nut, for Panel Mount), Set Pressure: 1 (0.02 to 0.2 MPa Setting), Exhaust Mechanism: Relieving Type, Flow Direction: Left to Right, Knob: Y (Upward), Pressure Units: Z (Unit on Product Label: psi, Pressure Gauge: MPa/psi Dual Scale)

Size: 1/8, Port Size: 1/4, Size 20, Accessories: Panel Mount Nut, Handle Orientation: Handle Down

Special Applications: Clean Series, Body Size: 20, Reverse Flow: No, Thread: NPT, Port Size: 02 [1/4 (Size 20, 25, 30, 40)], Accessory, Not Attached: H [Set Nut for Panel Mount (Size 20 to 40)], Option: Nameplate/Caution Plate for Bowl in Imperial Units

Special Applications: Copper, Fluorine & Silicon-free+Low Particle Generation, Body Size: 20, Reverse Flow: No, Thread: NPT, Port Size: 02 [1/4 (Size 20, 25, 30, 40)], Accessory, Not Attached: H [Set Nut for Panel Mount (Size 20 to 40)], Option: Nameplate/Caution Plate for Bowl in Imperial Units

Regulator, Pressure Boosting Valve: Regulator, Regulator Type: Standard, Shape: Standard, Operating Environment: Standard, Compatible Fluid: Air, Exhaust Mechanism (Air Bleed): [Included] Relief, Reverse Flow Function (Relief): No, Supply Side Connection Type: [NPT] NPT, Supply Side, Connection Diameter: 1/4, Flow Direction: [Right] From Left to Right, Control Side Connection Type: [NPT]

Regulator, Pressure Boosting Valve: Regulator, Regulator Type: Standard, Shape: Standard, Operating Environment: Standard, Compatible Fluid: Air, Exhaust Mechanism (Air Bleed): [Included] Relief, Reverse Flow Function (Relief): No, Supply Side Connection Type: [NPT] NPT, Supply Side, Connection Diameter: 1/4, Flow Direction: [Right] From Left to Right, Control Side Connection Type: [NPT]

Size: 1/8, Reverse Flow: Regulator, Standard, Thread: NPT, Port Size: 1/4, Accessory: Panel Mount w/Set Nut, Option 1: None, Option 2: Name Plate & Pressure Gauge in Imperial Units, PSI, °F, Made to Order: For High Pressure