NinjaFlex Grass Green TPE 3D Printing Filament - 1.75mm NinjaFlex is one of the strongest yet most flexible filaments you can find. NinjaFlex is incredibly easy-to-feed and is ideal for making parts like iPhone cases, iPad cases, and bracelets. You can make anything that requires some bend and flex while maintaining strength. NinjaFlex has a shore hardness of 85a meaning it is softer and more flexible than MatterHackers TPE and Soft PLA Free same day shipping on all orders