Could Forming Channel with Foam inside, H.D.G, Used for Connecting in Concrete. JBS has many years production experience. Could Forming Channel with Foam inside, H.D.G, Used for Connecting in Concrete.The sizes contains as below:28/15 x 100, 150, 200, 250, 350, 400, 550, 800, ...28/15 x 100, 150, 200, 250, 350, 400, 550, 800, ...49/30 x 150, 200, 250, 350, 400, 550, 800, ... Cast-in Channel