We offer a choice between stainless and nylon compression rings/sleeves.

• Stainless Ferrule: This is a set of rings/sleeves/ferrules that slip over the tubing, but behind the compression nut that get squeezed onto the tubing when you lock the nut down TIGHT for the first time. This process permanently crimps the rings to the tubing though you can still remove the compresison nut and tubing (though the nut is now captured). This option is more difficult to use and requires a lot of torque to set, however it is the better mechanical option where a lot of stress is put on the connection.

• Nylon (AKA Delrin) Sleeve: This option replaces the pair of stainless rings with a one-piece wedge ferrule made of a tough, high temp, food grade plastic. It seals well with minimal tightening on the nut (hand tight plus a quarter turn), never attaches itself to the tubing permanently. Although it is plastic, it does allow for many disconnection cycles without wearing out. The only down side is that it doesn't offer the same mechanical strength as the SS version in cases where a LOT of stress is put on the connection. We recommend this for anything except for mounting HERMS coils where the full weight of the coil is supported by the compression fittings (however we have gotten reports that nylon works OK so give it a try if you want to).