620310-2NSE9 Nachi Sealed Bearing 5/8" inch x 40mm x 12mm Made in Japan 620310-2NSE9 Nachi Bearing, Made in Japan, the 620310-2NSE9 inner diameter is 5/8" inch, the 620310-2NSE9 outer diameter is 40mm, 620310-2NSE9 width is 12mm.