In Australia, a common type of phone was the Telecom TF200 (of the T200 series). Other names for phones of this type are Telecom Touchfone, Telstra Touchfone and Telstra T400.

If you wanted to stick it to a wall, there was a wall mounting kit, which came with pieces to (a) attach the phone to the wall, and (b) a small bit of plastic to stop the handset (usually held on by gravity) from falling as far to the floor as the cord permits. This is what the handset hook (or handset clip) does.

This is a model for that small bit of plastic to hold the handset. The part stays in with friction, unlike the original part.