Previously used by the British Army medical
Listing is for one of the three shown in the photos
Manufactured by GCE Mediline
Designed for use with low pressure regulated gas
supplies
Can be used in conjunction with trolley mounted
regulators or piped supplies
The robust design, simplicity of operation and
accuracy provide significant benefits over traditional glass or plastic flow
control devices
Manufactures details can be found here – https://www.gcegroup.com/en/products/mediflow-ultra-ii