These are definitely needed on metal to metal connections to complete a solid leak proof seal.
W
William Munoz
Use a twisty tie
These things are great for making your mfl connections compatible with commercial taps. Just use a twisty tie or string to store a bunch of these as they do like to disappear.
F
Frank Mitchell
Now a Believer
When you start kegging, teflon tape can get sticky, environment can break it down. Use these with every metal on metal connection, especially when building a keezer and save yourself a CO2 tank refill because you couldn't hear the leak.