Deltana GL8522-12ATK Resin Flush Ceiling Lamp, 15-1/2" x 7-3/8"

The GL8522-12ATK measures 15-1/2 x 7-3/8 inches, with a 12 inch diameter given separately. Use the 12 inch figure for the ceiling footprint when you're spacing fixtures in a corridor or laying out a grid in a room, and hold the 15-1/2 inch number for the overall envelope so you know the box will clear once it's open.

Residential. Deltana specs the GL8522-12ATK for residential use, so for a hotel corridor, a school hallway, or anywhere your AHJ is going to want a commercial-rated luminaire, look at a fixture spec'd for commercial duty instead. It's a reasonable pick for single-family rentals, condo units, and apartment interiors where a residential fixture is what the job calls for.

Treat it as a one-time buy. The GL8522-12ATK is a clearance item, so it isn't the fixture to build a multi-unit standard around if you expect to reorder the same model in a year for turns and replacements. If you're doing a defined scope now, say a full floor or a fixed unit count, buy the whole quantity in one go. For a rolling standard you want a fixture in the regular line.

Flush ceiling mount. It sits up against the ceiling plane rather than dropping on a rod or chain, which is what you want in a low-ceiling bedroom, a hallway, a closet, or a stairwell landing where headroom matters and a pendant would be in the way.

GL8522-12ATK is the Deltana model designation, from the Resin Flush Ceiling Lamps series. The 12 in the number is the size, listed as a 12 inch product size. Quote that full string rather than just GL8522, since the size is baked into the part number.

Resin, both the substrate and the finished surface. It's sold as a single resin finish option rather than a range of plated metal finishes, so what you see is the material itself and not a coating over something else.