HobbyKing is a brand, distributor, and online retailer of radio controlled hobby products. Their retail lines consists of their own branded products "HK" or "HobbyKing". Additionally, they sell products from around the world such as Align, E-flite, and many more.
The HobbyKing brand, specifically, is made up of a massive selection of products that range from motors, ESCs, batteries, airplane kits of all completion levels (ARF, PNF, RTF, Kit, etc), helicopter kits of all sizes, and cars, trucks, buggies, and more.
Their airplane category alone contains some 1000 kits ranging anywhere from scale composite or balsa models with large wingspans down to sheet electric foamies and molded foam kits. Included in the mix are trainers to advanced flyers and scale models to flying wings. HobbyKing kits also include both electrics and gas/nitro powered aircraft.