What is the purpose of this optional metal DIN rail clip?

This optional metal DIN rail clip is designed to provide a mounting solution for Pertech's 508TX and 509FX devices, allowing them to be securely attached to a standard DIN rail.

Which Pertech products is this DIN rail clip compatible with?

This metal DIN rail clip is an optional accessory for the 508TX and 509FX models. It is also noted that a similar clip comes standard with the 516TX and 517FX devices.