20" diameter, 1 year warranty (we will fix/replace it for free at our store in Crystal Lake).  Comes with optional deck mount. You have three other options to mount this bath.  You can put it on one of the free standing holders (the Three Leg Metal Stand or the Ivy Leaf Birdbath Stand).  Both come with stakes so you can stake each leg into the ground for extra stability.  It is still very stable without the stakes, so if you are putting it on a deck or other solid surface where you can't use them, don't worry.  We also have a Deck Holder as well if you would prefer to put it on your deck railing.  There is a clamp but also pre-drilled holes if you would prefer to screw it in.  Try putting the Layered Waterfall Bubbler in this bath to attract even more birds.