When sourcing double disc couplings, you must prioritize torque capacity (both nominal and peak) and misalignment compensation capabilities. Ensure the discs are made of high-strength stainless steel (e.g., SUS304 or SUS316) to provide the necessary flexibility without permanent deformation. For high-speed applications, verify the dynamic balance grade (G2.5 or G6.3) to prevent vibration. Additionally, check the bore diameter tolerances and the clamping method, such as setscrew, clamp-style, or keyway, to ensure a secure fit with your motor and driven shafts.