Training clicker which is great for training your new puppy or dog. Easy to use elevated button for fast clicking in any position and it is small so it is easy to carry wherever you go. Also comes with a band so it can hand on your wrist so you do not worry about losing it or having to hold it in your hand the entire time.However if you are not a fan of having it around your wrist you can easily detach the strap. Shape of the clicker fits nicely into the palm of your hand and it is very easy to click while holding something else in your hand such as a leash or a toy. Perfect for a dog owner or even a dog trainer. Comes in one size only.