The 1N6355/TR is a 200 V Zener diode from Microchip Technology in the standard B, Axial (DO-41-equivalent) package. The 500 mW power dissipation rating sets the thermal budget for continuous voltage reference or transient clamping applications — at 200 V the maximum steady-state current is about 2.5 mA before hitting the 500 mW ceiling. The ±5% tolerance is typical for general-purpose Zener diodes used in voltage regulation, overvoltage clamping, or as a reference in bias networks. Reverse leakage is specified at 50 nA maximum at 152 V — low enough that it won't load down a high-impedance node in standby or sleep circuits.
That makes this part suitable for avionics, downhole instrumentation, or engine-bay electronics where the ambient can exceed 125°C. The B, Axial package (DO-41 footprint) is a through-hole form factor — it inserts into a 0.025-inch round hole on a standard PCB or protoboard. The Tape & Reel packaging indicates this variant is supplied on a reel for automated insertion equipment, though the part itself is through-hole, not surface-mount.