When connecting -6AN (37 degree flare) hose assemblies to -6AN fittings such as those on the Pulsefire Backpack Kit, you’ll want to use soft copper flare seals to absolutely ensure that the connection is leak-free for safety. The Pulsefire Backpack Kit includes 2 seals, but these are handy in case you damage yours or lose them when switching back to handheld.
Pack of 4 seals.