Pressure temperature guide #2. One side is R22 replacements (R22, XP40-R449A, M029-R422D, NU22B-R422B, R407A, M099-R438A, R407C, R410A). The reverse is R12 and R502 replacements (R134A, R513A, R437A, R507A, R404A, R449A, R422C, R417C). Can be folded down to pocket size for easier carrying.