Sealey Air Conditioning Rubber O Ring Assortment 225pc Metric ACOR225Manufactured from HNBR. Designed for use with Freon R134a and R1234YF gas making them suitable for automotive air conditioning units and many other applications. Specifications Detail Made from HNBR. Detail Designed for use with Freon R134a and R1234YF gas making them suitable for automotive air conditioning units and many other applications. Contents (Approximate Quantity) ID x Thickness; 3 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,