I was looking a while back for a bulk pack of the correct type magnets for the Iris sensors I bought that didn't come with magnets. I looked everywhere, but they either were VERY expensive ($8-10 each), or were just not available. Even the generic alarm sensor magnets were so expensive it didn't make sense even use the Iris, would have been cheaper to just replace them.
I also looked for a bar or strip magnet, that would look similar in form to the sensor's magnets, and there were pretty slim pickings there too.
I did end up just buying some round ones. They work, but are ugly as can be if you either space them out to the correct plane, or mount them on edge. I am considering drilling (or routering) the top of the doors and place the sensor inside the door itself, and mount the magnet in the door frame.
