What the ratings mean for a protection design
The 1.5KE36: The DO-201AA axial package (DO-27 equivalent) is a through-hole form factor suited for point-of-use board-level transient suppression where a replaceable, inspectable solder joint is preferred over surface-mount.
Littelfuse lists the 1.5KE36 as Obsolete. For a design still carrying this part number, the procurement path is surplus or broker inventory; a board-spin to a current-production TVS diode in the same package and voltage class should be evaluated for new builds.