The K-200 has almost double the volume of the K-100. This is a must pump for all rafts, catarafts and pontoon crafts because you can stand upright when using it. The pumping action is effortless, yet highly efficient. The K-200 is designed to be the best pump for "topping off" you have ever seen. There is simply no comparable pump that will produce as much air volume with less effort. Commercial river guides acclaim this pump to be about as valuable as their floatation jackets. If you have a back problem, this is your pump! A quick demonstration at a K-Pump dealer will quickly prove its value.