The ball-bearing guide matches the cutting diameter, and the long shank allows multiple-pass routing for deep cavities.
The 1/2" diameter bit is recommended for most of your routing chores, and comes with 1 bearing. Use the 3/8" cutter only for routing corners that need the tighter radius, it comes with 2 bearings.
Sold individually or SAVE when you buy the set of both router bits.
Shank diameter: 1/4" (6.35mm)
Cutting height: 1/2" (12.7mm)
A heat-resistant sleeve (not shown) holds the bearing in position. We recommend stacking an extra bearing on the shank for deep cavities, and use the 3/8" bit only for routing corners.
Tip: We recommend that you change the position of stacked bearings on the router bit's shank every time your re-chuck in the bit into your router. This will greatly extend the life of the bearings and reduces the risk of a bearing "blow-out."