Caliber 200 mm.
There is currently no 7-inch hose on the market. You can use an 8-inch hose, which is a hose with a diameter of 200 mm, to connect to the water pump. When connecting, you can use a rubber pad to cushion it and then put it on. Just tighten the water hose with a clamp.
The nylon canvas hose is easy to roll and easy to use, especially when working in low temperature environments. The nylon canvas hose has stronger frost resistance, while the plastic pipe is harder and heavier and is not convenient to roll up. It is easy to freeze and burst the pipe when used in a low temperature environment.