The Mountain High oxygen bottle neck extender (3/4-16 port) is a useful addition when your oxygen bottle needs clamping in place.
This unit extends the area between the cylinder neck and the valve to allowing clamping in this area.
The air coming through the extender is filtered and the unit comes with o-rings for sealing.
The standard diameter of the extender is 1.76" (44.7mm).
See 'Neck extender drawing' below for specifications.