You’re looking for a 1/8" BSP Male Thread Manual Heat Pump or Radiator Air Vent Valve a handy component for heat pump radiator heating systems!

• Air Vent Valve: Made of nickel-plated brass, it’s corrosion-resistant and durable. It doesn’t require a key for operation.
• Compatible with most, GSHP, ASHP, EAHP, VVMS, EVP SYSTEM