87mm Grant Piston Rings For Aircooled Volkswagen 1641cc Engines. Groove Size 2.0 X 2.0 X 5.0, Set Of 4, These Ring Sets Contain Compression Rings Which Are Manufactured To Precision Specifications From High Grade Grey Iron Castings The Top Compression Rings Are Black Phosphate Coated And Normally Beveled On The Inside Top, Which Gives A Torsional Twist Characteristic Or Relieved On The Lower Ridge For Oil Scraping Characteristics. The Second Compression Ring Is Normally A Scraper Ring Commonly Used In The Second Groove. Oil Rings Are Generally 3-Piece Circumferential Style, Which Provide Quick Seating, Positive Oil Control And Long Life