Applied properly, these loops are strong enough to support the heaviest shade, and add to the appearance of any lampshade upon which they are used. Wireway hole will accommodate lamp cord. 2-1/8" high. They are threaded or tapped 1/8 I.P., which is just right because that is the size of all the brass nipples, sockets, couplings and other stuff we sell. However, if you plan to use one on top of a harp, you will need a #6627 Reducing Bushing.