Based on this product's specifications, here are some alternatives and similar models
Belt clip MITEL 622/650, black, durable design for headset/handset mounting
Summary description:
Replacement belt clip for MITEL 622/650 models in black with a durable design. Provides secure mounting for headset or handset, allowing hands-free carry and easy access during work. Simple to attach and remove, compatible with specified MITEL models. Practical for office, field service, retail staff and other users who need convenient on-person storage.