I replaced the OEM spikes from Polk with some brass spikes from Brass and Granite Audio. I figured I would give these a shot at least for the looks over the plastic ones. I was surprised at the end result, they definitely allow more room for placement. I placed the 1.5" spikes in the rear and the 2.10" spikes in the front which sort of angled the 12s up just a tad. These do allow you to adjust them even more. So I was able to get the tweeter just right; aimed right between both rows of my H/T seating. Anyway, thought I would share. A worthy buy as they make the speakers look even better. Anyone interested Polk threads are 1/4-20.