When am I supposed to use Brass tube support sleeve

[Chefwong]

When am I supposed to use Brass tube support sleeve when working with compression fittings ? For every compression fitting ?

 

[Handygirl911]

I never use those tube inserts, only the ferrols. My plumbing has never leak.

 

[Sponsor]

 

[Lancaster]

You use them with polyethylene tubing.

 

[Winslow]

they are used when using plastic pipe. It prevents the pipe from just collapsing, allowing the ferrule to grab the pipe.