NdFeB Countersunk Magnet Ring Tapered Hole Ndfeb Magnet https://www.mlmagnet.com/product/ndfeb-countersunk-magnet/ring-tapered-hole-ndfeb-magnet.html Ring tapered hole NdFeB magnet is a ring magnet that is constructed in various sizes. The Ring tapered hole NdFeB magnet is available with either the same or opposite magnetic poles on the two surfaces, and can resist being demagnetized. The external powder coating protects the surface by reducing friction and moisture absorption.