Made of 100% US laboratory grade PTFE, these sleeves are temperature resistant to 500F, highly nonstick (relative for our purposes), soft, flexible, and chemically resistant.
Especially since the sizing of glass ground joints is variable, trimming the end can be necessary.
Otherwise, the best method to affix these is to first apply them to the male joint. Twist and push to get them as far along as you can, and then simply use the part as normal.
Alternately, assemble the joints as you would normally with the sleeve between them and push/twist them into place.
In some cases, especially brand new, they may be too nonstick, and your joints will swivel (especially with heavy weight or odd angles). In such a case, breaking in the joint protector can help, much the same as breaking in new shoes. Simply put it between two joints, press, and twist back and forth gently to help the material contour. Once a little bit of oil gets in place, however, they will have extra grip.
In the extreme case where the sleeve cannot be removed, there are two methods to try.
Gently warm the area with a heat gun (or hair drier) to melt any oil that may be holding it in place, then try again.
Freeze the stuck parts. PTFE has a greater thermal expansion rate than glass, and will shrink considerably. Depending on if or how much or what kind of oil is present, freezing may help render the oil brittle enough to come apart or simply not help.
10mm: Use between a 10mm male and 10mm female joint. This includes 10mm male nails in 10mm female rigs and vice-versa.
14mm: Use between a 14mm male and 14mm female joint. This includes 14mm male nails in 14mm female rigs and vice-versa.
18mm: Use between an 18mm male and 18mm female joint. This includes 18mm male nails in 18mm female rigs and vice-versa.
14mm to 10mm Reducer: Use between a 10mm male and 14mm female joint. This includes 10mm male nails in 14mm female rigs and 14mm female nails on 10mm male rigs.
18mm to 14mm Reducer: Use between a 14mm male and 18mm female joint. This includes 14mm male nails in 18mm female rigs and 18mm female nails on 14mm male rigs.