This works so good and I have been using this on my dog. If you have a problem with your dog running over and past the articles this may be your solution. This small plastic box has hinged lid that has air holes in the top of the box. The box is 2.5" x 4" so the dog can not grab it and swallow it. What you do is to put something that the dog likes, I suggest well aged meat that has a good strong scent to it put in the box. When you are tracking the dog and they get to the article that they are to stop at then they will be drawn to stop and smell this smelly ripe box. Then you down your dog until you open the box and give them the reward for stopping and staying at the article. The holes are only on the top of the box so any juices remain in the box helping to add to the scent. Colors Vary.