A gas storage assembly. The assembly comprises a gas cylinder, a tap fixed to the gas cylinder, a cover with a shell protecting and housing the tap. The shell includes a front face with a hand-wheel and connecting plugs, a rear face on the opposite of the front face, a first element, and a second element. The rear face comprises a rear opening formed in both the first element and the second element which are an upper half shell and a lower half shell respectively. A rear closure part closes the rear opening and is removably mounted to the lower half shell and to the tap. The opening provides a wide view for mounting and testing the tap when mounted to the gas cylinder.