This unit has been saved in our garage since it was removed from a house being remodeled requiring a larger unit. This unit uses the new standard R-410A gas. It was built February 2018.This one is a 30,000 btu (2.5 ton) built for 1,250 - 1,500 sq ft home.SEER is 14.2 single stage. A low pressure of 240 and a high of 450 pounds. See Goodman Model GSZ140301KG and Serial 1802092236. This unit was operating perfectly when removed. Selling for $600. Thank you for considering.