The 3/8 x 5/8 x 5/32 Revolution Series bearings are a low friction bearing with several options to help satisfy anyone's desire. What makes this bearing unique is that it has a rubber seal on one side while having a metal shield on the other. Rubber seals are great protectors against dirt but the price is that they offer a little more friction due to the tighter seal.
3/8 x 5/8 x 5/32 Revolution bearing by Avid Racing Concepts is the standard bearing for Associated diff outdrives. Check your manual for the correct size for your vehicle if you are not certain.