Click the picture above to purchase one on Amazon!
It is totally worth it! I plugged it in behind a cabinet and then hid the remote under my desk. I created a pocket full of math questions and placed them at my door with a sign that reads...Answer ME! When we have a little break in time or I need to get their attention I press the remote under my desk and it MAGICALLY rings. The class is trained to go to their seat and raise their hand. I then call on one to read the question and we answer it together.
Just remember friends, sometimes it is the little things that make all the difference:)