This new style bulk head fitting no longer uses the hard to find 5mm ferule.
Gone are the ferule and the brass sleeve that used to slide up inside the air line.
The new fittings are designed to be reusable with no parts that need to be replaced before re-installation.
These will work on new lockers with the smaller 3.5 MM copper line and also as replacement upgrades to older lockers bulk head fittings when upgrading to the new style seal housings with 3.5 MM copper line.
WILL NOT WORK ON OLDER 3/16" COPPER LINE USED IN OLD STYLE SEAL HOUSINGS!