M6x52 Buna-N O-Ring, 70A Durometer, Round, Black, Buna-N, 52 mm ID, 64 mm OD, 6 mm Width (Pack of 5) Made of Buna-nitrile for use with a variety of fluids and hydrocarbons Durometer (hardness) of 70A Round cross-section provides a seal between cylindrical overlapping surfaces For use across a wide temperature range from -40 degrees F (-40 degrees C) to 212 degrees F (100 degrees C)