Super Precision Ball Bearing 7910CYU/GLP4 Nachi Angular Ball Bearing Phenolic cage, Flush ground single unit 15 degrees Contact Angle Abec-7 50mm x 72mm x 12mm Made in Japan 7910CYU/GLP4 Nachi super precision Angular Ball Bearing with 15 degrees contact angle and Phenolic cage, bearing is ABEC-7 (P4) quality and made in Japan.