This listing is for the Inner Cam Bearing used on Single Cam Big Twins. This is the only cam bearing you should use for your Big Twin. These are made in the United States by Timken who acquired Torrington in 2003. The bearing offered is the B-138, which is suitable for Big Twins. May be used on OEM, aftermarket and S&S Motors for Single Cam models from 1958 to 1999.