Two different light sources that behave differently in an optic, not two grades of the same thing.
An SMD board spreads many small emitters over an area. A COB module puts the emitting surface in one dense block. A reflector can collimate a small, dense source; it cannot collimate a large, spread-out one.
If you need a defined beam — anything at or below 36° — you need COB. If you need smooth, wide, even light and a shallow body, SMD is the better and usually cheaper answer. That is exactly the split in this catalogue: the DL830 SMD downlights are fixed at 60°, and everything with a 15° or 24° option is COB or a COB-holder build.
Holder sizes — 1304, 0202, 1204, 1507, 1313, 1313-08, 1616-11 — describe the footprint the module sits in. They are listed on every product page because they determine which LED brands and which output bins can be fitted to your order.
Common and sensible: COB accent on the merchandise, SMD downlights in the stockroom and corridors. Keeping colour temperature consistent across both is the thing to specify carefully.
Send us the room and the ceiling and we will tell you what we would specify and why.
