Which type of special Postal Service would you use for a heavy expensive piece of medical equipment being return?

For returning a heavy and expensive piece of medical equipment, I would recommend using USPS Priority Mail Express or a private courier service such as FedEx or UPS with their respective insurance options. These services offer reliable tracking, expedited shipping, and insurance coverage, ensuring that the equipment is safeguarded during transit. Additionally, choosing a service that allows for signature confirmation upon delivery can provide extra security.