4" wide. Specify desired length when ordering. When you need more than one Mag-Stop Plate to cover an area, how do you handle the joints? Joint-Shield is the perfect solution! This is a generous .010" thick, fully hydrogen annealed magnetic shielding alloy with adhesive backing (rated 0 - 200°F) on one side. Simply butt the Mag-Stop plates tightly together, and "tape" over the seam with Joint-Shield high permeabilty alloy. This method offers much less bulk and better appearance than the old overlap technique and provides excellent shielding integrity. Simple to use: just cut to desired length with a heavy scissors, peel the protective backing and press into place! Joint-Shield can also be used by itself as an excellent magnetic shielding material when a 4" width and adhesive backing is desirable (wrap it around wiring and conduit, speaker magnets, even small appliances like shavers and hair dryers!). Joint-Shield can be shaped by hand, without the need for special tools, but watch the sharp edges.