Clamping voltage and standoff — where the protection window sits
The 1.5KE13CA-E3/73: That 7.1 V window between standoff and clamp defines the margin the downstream circuitry must survive.
Through-hole DO-201AA axial package — board-fit note
Supplied in tape-and-box (TB) format, the DO-201AA (DO-27) axial body mounts into a 1.1 mm diameter through-hole on the PCB. The bidirectional channel means a single device protects both polarities — no need for two series diodes or a bridge.