1. This series of slewing bearing are mainly made up of inner and outer rings. It features compact in design and light in weight. The balls contact with the raceway at four points, via which the axial load, radial load and tilting moment may be transmitted simultaneously. 2. The n1 means the number of lubricating holes, equally distributed, lubricating nipple M10×1 JB/T7940.1. 3. Those given in following table are our company's standard bearings. We can also manufacture the special bearings according to the customer's requirements. http://www.lidaslewingbearing.com