Monoprice MP Specialty 3D Printer Filament Flexible TPE Black 1.75, 0.5kg/spool - Monoprice.com
Filament Spool, 1.75mm, TPE, Midnight
Black PRO Series Flex - 1.75mm Flexible TPE (0.5kg) | MatterHackers
Amazon.com: eSUN Flexible TPE Filament 1.75mm, TPE-83A 3D Printer Filament, 1KG Spool 3D Printing Filament for 3D Printers, Black : Industrial & Scientific