Elite Tap In and Elite Tap In with Spike are magnetic catches, also designed to be flush mounted, and tapped in beneath the surface of the wood. They will continue to work over an air gap to offer a near silent and sophisticated, smooth closure. These Elite catches come threaded to hold them securely in place. BUYMAGNETS.com tests on a flat, machined steel plate, 1/2” thick. If the surface is rough, rusty or painted, the holding force may be reduced. For critical applications, build in a safety factor of two or three.