When evaluating hardware like vacuum pumps or traction extenders, prioritize medical-grade materials. For pumps, ensure the cylinder is made of high-transparency, shatterproof polycarbonate and the sleeves are skin-safe, phthalate-free silicone. For traction devices, look for adjustable tension scales and ergonomic padding to prevent skin necrosis. If sourcing electronic models, verify USB rechargeable lithium batteries with overcharge protection and a noise level below 50dB for consumer privacy.