What the ratings mean for circuit protection
The 1.5KE220-B: The 185 V reverse standoff voltage means the device does not conduct at normal line voltage up to that level; it only clamps when a transient exceeds it. The 1500 W rating tells you the energy-handling capacity: a higher-energy surge than the diode can absorb will destroy it, so the TVS must be sized for the expected transient energy on the line.
Through-hole axial package, DO-201AA / DO-27 form factor, supplier device package DO-201. The axial leads suit point-to-point wiring or PCB through-hole mounting; the body is large enough to hand-solder without magnification. Supplied in bulk — no tape-and-reel, so it is a manual-placement part. Not a showstopper for a service stock or a low-volume build, but a pick-and-place line would need a tube or tray feeder.