Black CoexFlex™ 60A TPUBlack CoexFlex 60A TPU **60A is very soft and can be challenging to print with. We recommend a direct drive extruder with a contained filament path (it will squeeze out any gap it can) and a PTFE lined hot end (it tends to stick to the walls of an all metal hot end). Seasoning an all metal hot end may help.** CoexFlex 60A TPU is, by far, the most flexible filament on the market. At Shore 60A, it is much softer than Ninjaflex or Filaflex, feels like a