Kingstorm 5PCS Barrel M6 x 26.5 Nozzle Throat for Makerbot MK8 Tube 3D Printer Extruder Hot End

Agree with other reviewers. No PTFE inside, tube is too small to drill out and make room for tubing. Don't waste your money, this jams nearly every print I've tried.

PFTE tubing inside is pretty crappy. It turned into a soft gooey mess when just printing PLA at 206C.

Mine have no PTFE tubing either, and the inside of the barrel is very rough, which is the opposite of what you want. My extruder won't push filament through it. Don't waste your money.

No PTFE tubing on the inside. Not worth buying.