The Siemens 3RV1903-5BA00-0FJ0 is an indicator light with a glow lamp rated for 110-120V AC/DC, fitted with a color disc that offers red, green, and clear positions. It mounts into the 3RV19 housing family, covering sizes S00 through S2. This is the part you pull when the panel builder's BOM calls for a visual status lamp on a motor starter or circuit breaker enclosure.
The color disc ships with red, green, and clear inserts — you swap the lens to match the circuit state you're indicating. The glow lamp operates on 110-120V AC or DC, so it works across both control supply types without a separate rectifier. Housing sizes S00 through S2 cover the full 3RV19 breaker range, meaning one indicator SKU fits the whole panel family.