Abstract: An operator for remotely opening and closing the valve on a gas cylinder includes a metal frame having an enclosed upper portion, a support plate extending across the upper portion and a mounting wall extending downwardly from a side of the upper portion. On the mounting wall is a C-shaped clamp which is adapted to extend around and be secured to a non-cylindrical portion of the cylinder valve to secure the frame to the cylinder. On the mounting wall below the clamp is an additional clamping means which extends around a cylindrical portion of the cylinder to further secure the frame to the cylinder. A pneumatic activator is mounted on the support plate and has a shaft extending through an opening in the support plate in alignment with the valve stem of the cylinder valve. A coupling member is on the shaft and connects the shaft to the valve stem.