Like an idiot, I accidentally used our tamper without the lid and the blades cut a hole in the bottom of the tamper.  The tamper is hollow, so one doesn't want to use it if there is moisture inside (mold, etcetera).  I wish this tamper had a bit thicker wall, as I think the bottom where the injection molding tap is cut off leave the most vulnerable part of the tamper, closest to the blade.  But nothing beats a Vitamix and the tamper.  Love this product.