Features: Aibecy flexible shaft coupler has capability to remove stress when shaft is not aligned. Suitable for connecting two axis with different diameters, also can be connected with a motor axis.Compatible with NEMA 17 stepper motors (for 5mm / 8mm shaft diameter). Pacakge comes with 2pcs couplers in size 14*25mm / 0.55*0.98in (D*L); there are two colors and two inner diameters for your option. Made of alluminium alloy, upgrade components guarantee the efficient operation of the 3D printer.