This Router Bit Replacement Bearing features an outer diameter of 1-1/8", an inner diameter of 1/2" and a height of 5/16". Typically, bearings with a 1/2" inner diameter are used on the shanks of template or flush trim router bits with 1/2" diameter. This high quality ball bearing is well constructed and will endure many hours of use. This bearing can also be used as a standard utility bearing in whichever application that bearings are used.Highlights:- Replacement shank bearing for router bits with a 1/2" shank- Polished stainless steel construction for smooth and worry-free operation- For router bits with a 1/2" shankItem Includes:1 BearingFrom time to time, router bit bearings need to be replaced due to normal wear and tear. Because you never know when a bearing will suddenly seize or break, it's always a good idea to have a few extra bearings around. Bearings with an inner diameter of 1/4" or 1/2" are often used as shank bearings for template or flush trim router bits with shank diameters of those sizes. Bearings with a 5/16" inner diameter are used as part of a router bit assembly, common in tongue & groove and rail & stile bits, which are placed on a router bit arbor that has a 5/16" diameter. Bearings with a 3/16" inner diameter are used on the end of flush trim, edge forming or rabbet router bits with an end stub that has a 3/16" diameter. Our fully-enclosed bearings are smooth and well balanced and are made to withstand heavy use.