Check the listing for details. R410A Air Conditioning Charging Slide Chart. Condition: New. Listed at 9.95 USD. For sale is one new slide type calculator used for calculating R 410A superheat and 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 superheat for a NON-TXV system and the other side is a slide chart used to calculate subcooling on a TXV system. 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 3.25 inches wide. If you have any questions, feel free to ask and I will answer them to the best of my ability. I also have charts for R- 22 systems, low temp refrigeration and air duct sizing! Check them out in my ebay store while supplies last! Follow the link below to my ebay store!!http://stores.ebay.com/The-Heat-Cool-Store_HVAC-