For sale is one new slide type calculator used for calculating A2L subcooling. This is a very useful tool that takes the guess work out of charging cooling systems. One side of this tool is a slide chart used for calculating one type subcooling and the other side is a slide chart used to calculate another type subcooling. The photo shows both sides of the tool. This tool is made of thick durable water resistant paper stock with corner rivets. It fits easily in your shirt pocket at approximately 6.25 inches high by 3.5 inches wide.