SATCO Lighting S49991 10W, 3 Foot LED T8, Medium Bi Pin Base, 3500K, 50000 Avg Rated Hours, 1450 Lumens, Type A, Ballast dependent

It stays on the ballast. The S49991 is a Type A, ballast dependent lamp, so it runs off the fixture's existing fluorescent ballast with no rewiring and no socket change. That makes it a straight lamp-for-lamp swap for maintenance crews, but it also means the lamp only works while that ballast works: if the ballast fails later, you replace the ballast or move to a ballast bypass (Type B) lamp. Compatibility with your specific ballast model is confirmed on the manufacturer spec sheet.

1450 lumens at 10 watts. A 3-foot F25T8 fluorescent is typically rated around 2000 initial lumens but depreciates over life, so expect a modest drop in raw output with a substantial cut in wattage. For corridors, storage rooms, and back-of-house areas that is usually fine; for task areas where the fluorescent was already marginal, measure before you standardize a whole building on it.

3500K is neutral white, between the warm 3000K of hospitality spaces and the crisp 4000K to 5000K common in offices and warehouses. It is the usual middle ground for offices, schools, and healthcare corridors. If the rest of the building is lamped at 4000K, mixing 3500K in the same sightline will read noticeably yellower, so match what is already installed.

The lamp itself is listed as dimmable, but because it is a Type A lamp running on the existing fluorescent ballast, the dimming performance depends entirely on that ballast being a dimming ballast and on the control wired to it. On a standard non-dimming instant-start or programmed-start ballast you get full output only. Check the ballast model against the Satco spec sheet before you quote a dimmed install.

CRI is 80+, which is the standard commercial grade and matches what a typical 800-series fluorescent lamp delivered. It is adequate for offices, corridors, classrooms, and general retail. Spaces that specify 90+ CRI, such as color-critical retail displays or some healthcare exam rooms, need a higher-CRI lamp.

The S49991 has a glass body, and it weighs 0.31 lb. Glass tubes handle heat well and look like the fluorescent they replace, but for gyms, kitchens, food prep areas, and anywhere breakage is a concern, specify a plastic or coated shatterproof tube instead.

Rated at 50,000 average hours. On a 12-hour-a-day schedule that is roughly 11 years of operation. Worth noting on a Type A lamp: the fluorescent ballast feeding it will typically not last that long, so plan relamping cycles around the ballast, not the LED.