Ammunition Storage Components (ASC) is a manufacturer of firearm magazines and related accessories. The magazine you mentioned, "6.8 SPC 25 Rounds Flat Dark Earth AR-15," indicates that it is designed to hold 25 rounds of 6.8mm Remington SPC (Special Purpose Cartridge) ammunition. The magazine is compatible with AR-15 platforms chambered in 6.8 SPC.
The "Flat Dark Earth" (FDE) color in the description refers to the color of the magazine's finish. FDE is a popular color option for many firearm accessories and equipment, as it provides a subdued appearance and blends well in various outdoor environments.