I only put the ad up there as a reference, you can buy them at AutoZone, Advance Auto, or just about any auto parts store.
they do work nice though, just keep an eye on how much fluid is in the bottle, and empty as required to keep it safe.
another little trick is to tape a soupcan lid to the fork, for a flat steel place the magnet can stick to reliably, just a piece of ducttape will do, makes it easier.
