Installing flush- or panel-mount MFDs with one-way machine screws is another way to thwart would-be thieves. Also known as security screws, the heads of these allow you to tighten the screw against a nut, but they make it difficult to unbolt the fastener, enough so that a thief might give up. Some argue a thief might resort to cutting out the entire helm panel with a portable power saw, mangling the fiberglass in the process, but this is time-consuming, and the noise attracts attention. One-way screws can be removed, in case you want to replace an MFD, but it requires special techniques, more time than conventional screws, and usually two people. For bracket-mounted electronics, aftermarket locks that take the place of thumb screws help thwart thieves, Heffernan says.