RSN* series by Duplomatic, which are single-acting throttle flow control valves:

Specifications

• Type: Single-acting throttle flow control valve
• Mounting Style: Screw-in cartridge or inline
• Cavity: D-10 B
• Port Sizes: BSP threads — 1/4", 3/8", 1/2", 3/4", 1", 1 1/4", 1 1/2"
• Max Operating Pressure: Up to 400 bar
• Max Flow Rate: Up to 220 liters/minute
• Adjustment Mechanism: Conical throttle in a cylindrical seat for linear flow control
• Locking Feature: Adjustment knob can be locked in any position using a transverse grub screw