Water dispenser with separation between hot and cold water to prevent, temporarily, like on the Sabbath, heating incoming cold water with the hot water in the tank. The ventilation mask can have a gas delivery port with a gas delivery tube rotatably coupled thereto. The pry bar holder may further comprise a specially designed backrest that attaches the pry bar holder to a belt. The entire substrate in this state is exposed in a gas containing halogen fluoride to thereby remove the peeling layer and separate the element-forming substrate. A stairway may be built using uncut stringers by use of the invention. The device also incorporates a raised memory bit diffusion between the control gates to reduce bit resistance.