It’s a Hartzell Compact prop. Hartzell make/made two different types of constant speed prop, the earlier Steel Hub and the later Compact; this is the latter and can be characterised by the hub being made in two halves with the blades in between. On the Steel Hub the blades fit into sleeves bolted directly onto a spider.

The part number should be stamped on the hub adjacent to one of the blades. The part number should start with ‘HC’, the fourth digit should tell you how many blades. The blade to the right of the part number is Blade No.1.

At the tip of the dome is a schrader valve for pressurising the interior of the dome with nitrogen.

These are fitted to a range of aircraft types and come in many different variations; two, three blades, counterweights or not, feathering or not etc depending on application.