If you intend to extrude exotic thermoplastics such as ULTEM, PEEK etc, we would recommend that you buy either a Noztek Pro HT or a Noztek Touch HT with a pre-heater band. This will help to reduce the possibility of a barrel jam (due to the build-up of material in the barrel). Another recommendation is to purge the barrel after each extrusion run (please see our FAQ on cleaning the barrel.