This ScatMatŪ Extension works with your original ScatMatŪ purchase. ScatMatŪ and its extensions deliver a brief, startling static correction when paws step on it. Pets quickly learn to avoid the area that you designate "off-limits." This extension mat works with any ScatMatŪ Power Pack. It measures 30 x 16 inches-great for blocking doorways, or covering furniture. Intended for small to medium-sized pets.