Amazon.com: HJ Garden 4pcs 6mm Brass Hex Shaft Coupling Motor Flexible Coupler Joint for Connecting DC Motor Shaft, Robot, Model Car Tyre etc. : Industrial & Scientific
1" Solid Shaft Coupler w/ Keyway and Set Screws 3" Long | eBay
9/16" Hex Coupler HC916 - Shoup
uxcell Hex Coupler 4mm Bore Motor Hex Brass Shaft Coupling Flexible Connector for Car Wheels Tires Shaft Motor 2pcs - Amazon.com
Rigid Shaft Coupling, 126-2400 - Power Transmission Products | MDS of Michigan
1/2" Hex Shaft Coupler - VEX Robotics
Brass Connector 6mm Hex Coupling with Screws Flexible shaft coupler for Motor/Robot /small intelligent car
Part Number 13S006006PSC, Two-Piece Split Precision Sleeve Hex Bore Couplings On Stafford Manufacturing Corp.