Big Ford & Olds Pontiac Sealed Ball Bearing commonly found on 40 spline axles. There are a fully enclosed one piece ball bearing with an o-ring.  These 3.150" OD bearings fit in Big Ford New Style Torino Ends, Bird Ford Old Style, Lamb/Symetrical, Olds/Pontiac, Hybrid Chevy Ends, Hybrid Mustang, Hybrid Mopar Ends that accept a 3.150" Bearing. 

Bearing O.D: 3.150"
Bearing I.D: 1.771"

Includes:
(2) Bearings & (2) Press Rings