Review on HATCHBOX Purple TPU 3D Printer Filament - High Quality 1Kg Spool With +/- 0.03Mm Dimensional Accuracy And Shore 95A Hardness In 1.75Mm Diameter by Kendrick Dooley

Works really well as others have said slowing down the print speed to about 50-60% of PLA speed (about 20-30mm/s) seems to help a lot to avoid under extrusion. I'm using a custom extruder bowden style but with the PTFE tube just slit on the side for the extruder gear to push the filament through so no problems with binding up really. I did have some clogging initially but was previously printing with Nylon so think it was just residual nylon in the nozzle and hot end, cleaned out the hot end and replaced the nozzle and working great again. Much more forgiving in terms of printing than nylon, also much more rubbery but still a tough material. Great for print any sort of vibration dampeners (quadcopter parts in particular).