What the ratings mean for your BOM
The 1.5KE15AE3/TR13: Reverse standoff voltage of 12.8V means it sits across a nominal 12V bus without conducting leakage; the 14.3V minimum breakdown ensures it starts clamping before the downstream regulator's abs-max rating is reached. Unidirectional design — one channel, cathode band marked — so it protects a single polarity rail; for AC or bidirectional lines you would need two devices back-to-back or a bidirectional TVS.
The reel packaging (Tape & Reel) suits automated pick-and-place for through-hole axial insertion.
DO-201AA (DO-27) axial-lead package — through-hole mount, 0.052-inch lead diameter typical. The -65°C to +150°C junction temperature range covers military and industrial thermal profiles; store the reels dry, though the hermetic glass-passivated junction is not moisture-sensitive. No power line protection (MOV or GDT) — this is a pure silicon-avalanche clamp for signal or low-power supply rails, not a mains surge suppressor.