Cylinder straps (aka stage straps) provide an efficient means
of using bolt snaps to attach the cylinder to your harness hard points
(D-rings or sidemount rails). In some designs the strap may also be
used to help carry the cylinder. The strap itself is a piece of round
cord or flat webbing that creates secure attachment points for two
stainless steel bolt snaps. The strap encircles the cylinder's neck and
is secured at the cylinder's base by a stainless steel hose clamp. A
fabric sheath on the clamp is used to prevent the clamp from causing
damage to the cylinder or abrasion against the diver. Elastic hose
retainers are used to dress the regulator hose neatly against the
cylinder.
Metal to metal stage rigging, brass alloy, and boat style snaps are no longer considered best practice among experienced divers. Even the
best snaps can jam, but brass snaps are prone to jamming if not carefully maintained and they'll cut your thumb too. The boat snap (aka "suicide clip") is very effective as a line trap, and notoriously
ineffective as a reliable attachment device. It's also proven to be a bad idea to clip yourself to bottles that have the clips permanently attached to the tank using metal-to-metal rings or clamps. Should a jam or entanglement occur, a diver might find it impossible to free themselves from the bottle. Straps and stainless steel marine-grade
snaps that can be cut free in case of entanglement are now the accepted
form of stage bottle rigging.