Regulator won't fit

The regulator will not fit my cylinder

Each regulator suits one country's cylinders and pressure: UK 37 mbar click-fit (PM2138), Germany 50 mbar screw-fit (PM2141), Belgium and the Netherlands 30 mbar click-fit (PM2142), US and Canada screw-fit (PM2135). Buy Gozney's set for your country; never use an adaptor at the cylinder (the manual).