Two (2) pack of precision manufactured Replacement Teflon tubes for your Makerbot, CTC or similar 3D printers using the Mk7 or Mk8 extruder with the 2mm Inner diameter / 3mm Outer diameter Teflon (PTFE) tubes. Guaranteed to fit these models, and others with a 35mm long by 3mm liner on the extruder for 1.75mm filament (Note: This liner does not work on 3mm filament, or the newer style printer tubes that utilize 4mm Teflon liners (see our other listing for 4mm Teflon liners. Replace your extruder liner regularly, for improved printing quality, fewer print failures, and longer life. Note, this replacement liner is precision manufactured by TabSynth Design Works LLC as a third party replacement for your Makerbot Replicator or CTC printer, or similar printer using the Mk7 or Mk8 extruder and 2mm inner diameter x 4mm outer diameter PTFE liners. It is not in any way a licensed, approved, or supported by the printer manufacturer. The Flashforge name is a registered trademark of its owner, which is in no way associated with these liners or TabSynth Design Works LLC.