The disclosure relates to a sealed pressure container, which solves the problem in the prior art that a pump is required for providing air pressure in the container. The conventional product is inconvenient for carrying and is expensive. The sealed pressure container includes a body and a winding member. The body has an open end and a flexible portion, the flexible portion is at least one part of the body at one side where the open end is formed. The flexible portion can be wound around the winding member from the open end to provide air pressure in the body by compressing the air inside the body. Thus, without using a pump, tennis balls can be prevented from releasing pressure by keeping in the low-cost sealed pressure container. The sealed pressure container is convenient for carrying and operating and has reduced manufacture cost.

A device for storing at least one game ball under pressure, the device having a container with a leak-tight cover and a casing arranged around, and at a distance from, the container, and a pump for pumping ambient air into the container. The pump can include an annular piston arranged between the container and the casing, a handle connected to the piston for moving the piston translationally along the container, a first non-return valve for admitting ambient air into a compression chamber between the casing and the container, and a second non-return valve, arranged between the compression chamber and an internal volume of the container, for transferring air from the compression chamber to the container.

A device for storing at least one game ball under pressure, the device having a container with a leak-tight cover and a casing arranged around, and at a distance from, the container, and a pump for pumping ambient air into the container. The pump can include an annular piston arranged between the container and the casing, a handle connected to the piston for moving the piston translationally along the container, a first non-return valve for admitting ambient air into a compression chamber between the casing and the container, and a second non-return valve, arranged between the compression chamber and an internal volume of the container, for transferring air from the compression chamber to the container.