Active production — 1500 W surge protection in a DO-201 axial package
The 1.5KE33CA/B: That 1500 W figure is the device's headline surge capacity — it tells you how much energy the diode can absorb in a single transient event before the junction fails. With a 28.2 V reverse standoff voltage, this part sits on a 24 V rail or a 28 V signal line and stays off until a transient exceeds 31.4 V (the minimum breakdown voltage).
Bidirectional clamping — one device for both polarities
This is a single bidirectional channel — the Zener structure clamps equally on positive and negative transients. That matters for AC-coupled signal lines, bipolar data buses, or any board where the surge polarity is unknown, because one part covers both directions instead of needing two unidirectional diodes back-to-back. The DO-201AA (DO-27) axial package is a through-hole form factor with a 0.052-inch lead diameter typical. Note that the spec explicitly states 'no power line protection' — this part is intended for secondary surge suppression on signal or DC power lines, not for clamping AC mains transients directly.