The LP Butane Clip-On Regulator has an overflow level indicator to allow visual gas level monitoring and convenient leak testing. The added safety feature EFV (Excess Flow Valve) comes as standard. EFV is an automatic hose safety feature that automatically cuts off 90% of gas flow if the hose is compromised. Features and Benefits Suitable for Calor 7/12kg and Flogas 7/13kg 28mbar Butane Snap-On Regulator With Quick Release Fitting Inlet size 21mm Overflow Level Indicator EFV Safety Feature 85cm Crimped Hhose Additional Safety Features As Standard Specifications Dimensions: H:33.0 x W:24.0 x D:7.0 cm Guarantee:1 Year Model Number: 8517-FL-QR