The PX and RX with Nema output faces (Inline: PX23, PX34 and PX42; and Right-Angle: RX23, RX34 and RX42) shaft details are shown below.
The Nema23 (Inline PX23 and Right-angle RX23) has a flat on its output shaft.
The Nema34 and Nema42 have keyways. Keys are not included as standard from the factory; these are standard dimension keys.
Keys on the metric gearheads are included as they're oval shaped (not rectangular).