Highly saturated nitrile butyle rubber works with R-12 and R-134a. Packed in a rugged plastic storage case. Assortment contains: (20) 7/32×1/16 (20) 1/4×1/16 (20) 6.8×1.9 (20) 5/16×1/16 (20) 7.8×1.9 (20) 8×2 (20) 8.8×1.9 (15) 7/16×1/16 (15) 7/16×3/32 (15) 11×2 (15) 12×2 (10) 13.9×1.8 (10) 9/16×3/32 (10) 14×2 (10) 15×2 (10) 17×2 (10) 11/16×1/16 (15) 11/16×1/8