FREON FRIENDLY O-RINGS - Designed for use with Freon R134a and R1234YF gas making them suitable for automotive air conditioning units and many other applications. HIGH QUALITY - Manufactured from HNBR rubber for use with automotive air conditioning systems. METRIC ASSORTMENT - 225pc assortment contains a wide range of metric sizes to suit a variety of applications. PARTITIONED BOX - Supplied in a partitioned box for easy storage. CONTENTS - (Approximate Quantity) ID x Thickness; Ø3 x 1, 4 x 1, 4.5 x 2, 5 x 2, 6 x 2, 6 x 2.5, 6 x 3, 7 x 2, 8 x 2mm (20 of each), 9 x 2, 10 x 2, 12 x 3, 13 x 3, 14 x 2.5, 17 x 2.5, 18 x 4, 20 x 2, 22 x 2mm (5 of each).