The 521-9053 is a T-3 1/4 miniature bayonet base neon lamp (B1A/NE-51) designed for indicator and status display applications. It operates at 105–125 VAC/DC with a nominal current of 0.3 A and an impedance of 220 kO, consuming 1/4 watt of power. The lamp delivers a rated lifespan of 25,000 hours, providing reliable long-term operation in control panels, instrumentation, and signaling equipment. Its compact form factor and low power consumption make it ideal for space-constrained applications requiring visual indication.