SATCO Lighting S21406 16W LED PL 4-Pin, 4000K, 1850 Lumens, G24q Base, 50000 Avg Rated Hours, Vertical, Type A, Ballast dependent

The S21406 is a ballast dependent (Type A) lamp, so it runs off the fixture's existing CFL ballast with no rewiring. Pull the old 4-pin CFL, drop this in, done. The flip side: if the ballast is dead or gets removed, the lamp won't light. For fixtures you plan to rewire to line voltage, you need a Type B ballast bypass lamp instead.

No. The S21406 has a G24q base, which is the 4-pin configuration used on dimmable/electronic-ballast CFL fixtures. A G24d 2-pin socket (magnetic ballast with a starter) will not accept it, and the two bases are intentionally keyed differently. Check the socket or the old lamp's base marking before ordering.

It is rated for vertical orientation. In a downlight or recessed can where the socket points the lamp straight down or up, that is what it's built for. For horizontally socketed fixtures, such as many wall sconces and some troffers, specify a horizontal-rated PL lamp instead so the heat sink and optics work as intended.

At 16 watts the S21406 puts out 1850 lumens, which is in the range of a 26W to 32W 4-pin CFL while cutting draw by roughly half. CRI is 80+, so color rendering holds up for office, corridor, and lobby use. For a one-for-one brightness match, compare against the lumen figure printed on the lamp you are pulling out rather than the wattage alone, since aged CFLs run well below their original output.

Rated life is 50,000 average hours. On a 12-hour-a-day commercial schedule that is roughly 11 years of service, versus the 10,000 to 20,000 hours typical of the 4-pin CFL it replaces. For MRO stock, that is the main argument for converting a whole floor at once rather than lamp-by-lamp as failures come in.

Because the S21406 is ballast dependent, the install only works if the fixture's CFL ballast is electronic and still healthy. Note the ballast make and model and its lamp-wattage rating off the label, confirm the socket is G24q 4-pin, and confirm the lamp sits vertically in the fixture. If the ballast is a failing magnetic unit, replacing lamps won't solve the problem and a ballast bypass conversion is the better path.

4000K is neutral or cool white, the common commercial color for offices, corridors, garages, and healthcare spaces. It reads noticeably whiter than 3000K warm white and warmer than 5000K daylight. If you are relamping a space in stages, keep every fixture in a given room on the same 4000K so you don't get a visible color split between old and new lamps.

Satco publishes a spec sheet for the S21406 covering the 16W input, 1850 lumen output, 4000K color, 80+ CRI, and G24q base data, linked from the product's spec sheet PDF. Submittal reviewers on institutional and government jobs usually want that sheet attached rather than a catalog page.

Frost. The diffused frosted envelope softens the LED sources so you get less visible pixelation and glare in open downlights and drop lenses than a clear lamp would give. Each lamp weighs 0.33 lb, light enough that it adds nothing meaningful to an existing socket or fixture load.