About Real KSG
The KSG is a bullpup 12-gauge pump action shotgun designed by Kel-Tec. It has two tube magazines which the user of the gun can switch between manually.Each tube holds a total of seven 2.75-inch (70 mm) 12-gauge shotshells or six 3-inch (76 mm) shotshells.

About Tokyo Marui KSG
About the Tokyo Marui KSG Gas Shotgun, it will have the exact functionality like the real KSG made by Kel-Tec. Whilst the company has taken pains to provide the it will look like the real KSG in terms of measurements and look (expect some inconspicuous markings), they have not made the tube magazines like the real one as the real KSG has two tube magazines with each holding 7 12-gauge shells which the user will switch from one to another manually. In the Tokyo Marui airsoft KSG, they cannot have a 3 to 6-shot capability if they want to have a tube magazine function like the real thing as there is no space for their mechanism. They can actually do it, but then the airsoft player will be given a single-shot capability and that will defeat the shotgun concept as an airsoft shotgun will have to fire more BBs in one trigger pull.