Product review (3 stars): Better than nothing but not as efficient as had hoped
There's a metal strip under the one side and a flange that goes between the stove and countertop.  The metal strip is supposed to hold the entire cap down and in place to the stove.  The idea for this item is great but 2 things are issues: one, the metal strip separated from the vinyl on both caps and two, since my counter is about 1/8 inch taller than my stove, the cap sits at an angle and does not prevent as much spillage as one would hope.  Things get caught up under the one side and overall it only helps cover the gap somewhat.  I will continue to use it as it's better than nothing.