This is a legacy product, and replaced byAR20-N02BG-Z-B, REGULATOR, MODULAR, AIRLINE EQUIPMENT, AR MASS PRO, DC, AR MASS PRO 1/4 MODULAR (PT), .66676 lb

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: G [Round Pressure Gauge w/o Limit Indicator (Size 20 to 60)], Option: 1+N+Z

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: None, Option: 1+N+Z

Special Applications: 10-AR (Clean Series), Body Size: 20, Reverse Flow: No, Thread: N (NPT), Port Size: 02 [1/4 (Size 20, 25, 30, 40)], Accessory, Not Attached: G [Round Pressure Gauge w/o Limit Indicator (Size 20 to 60)], Option: 1NZ (1+N+Z)

Special Applications: 10-AR (Clean Series), Body Size: 20, Reverse Flow: No, Thread: N (NPT), Port Size: 02 [1/4 (Size 20, 25, 30, 40)], Accessory, Not Attached: None, Option: 1NZ (1+N+Z)

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: BG [B+G (Size 20 to 60)], Option: Nameplate/Caution Plate for Bowl in Imperial Units

Special Applications: 10-AR (Clean Series), Body Size: 20, Reverse Flow: No, Thread: N (NPT), Port Size: 02 [1/4 (Size 20, 25, 30, 40)], Accessory, Not Attached: BG [B+G (Size 20 to 60)], Option: Z (Nameplate/Caution Plate for Bowl in Imperial Units )

Special Applications: Clean Series, Body Size: 30, Reverse Flow: No, Thread: NPT, Port Size: 02 [1/4 (Size 20, 25, 30, 40)], Accessory, Not Attached: BG [B+G (Size 20 to 60)], Option: 1+N+Z

Note) The set nuts of the AR-A series and those of the AR-B/AR-D series differ in size as well as part number.
The AR-A series catalog can be found here.
The AR-B series catalog can be found here.

SMC Regulator (With Backflow Function) AR20(K)-B To AR60(K)-B Series.Features· Specifications with a backflow function feature an inbuilt mechanism for quickly exhausting the air-pressure at the outlet side.

When assembling high-pressure special order products, AF20 to 60-*-A-X425 and AR20 to 60-*-B-X425, prepare a nipple for installation.

Body Size: 30, Backflow: K (w/Backflow Function), Thread: N (NPT), Port Size: 02 (1/4), Options: BG (B+G), 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)

Regulator, Pressure Boosting Valve: Regulator, Regulator Type: Standard, Shape: Standard, Operating Environment: Standard, Compatible Fluid: Air, Exhaust Mechanism (Air Bleed): [Not Provided] Non-relief, Reverse Flow Function (Relief): [Included] Yes, Supply Side Connection Type: [NPT] NPT, Supply Side, Connection Diameter: 1/4, Flow Direction: [Right] From Left to Right, Control Side Connection

Body Size: 30, Backflow: w/o Backflow Function, Thread: NPT, Port Size: 1/4, Options: B+G, Set Pressure: 0.02 to 0.2 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, Made to Order: -

Body Size: 30, Backflow: w/Backflow Function, Thread: NPT, Port Size: 1/4, Options: B+G, Set Pressure: 0.02 to 0.2 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, Made to Order: -

Body Size: 30, Backflow: w/o Backflow Function, Thread: N (NPT), Port Size: 02 (1/4), Options: BG (B+G), 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: K (w/Backflow Function), Thread: N (NPT), Port Size: 02 (1/4), Options: BG (B+G), 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)

Special Applications: Clean Series, Body Size: 20, Reverse Flow: No, Thread: NPT, Port Size: 01 [1/8 (Size 20)], Accessory, Not Attached: BG [B+G (Size 20 to 60)], Option: 1+N+Z

Special Applications: Clean Series, Body Size: 20, Reverse Flow: No, Thread: NPT, Port Size: 01 [1/8 (Size 20)], Accessory, Not Attached: None, Option: 1+N+Z

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: None, Option: 1+N+Z