These are instructions to make a home-made exercise wheel for degus; in this example, two exercise wheels were made -- one is 14" in diameter and the other is 16" in diameter.  In order to prevent a degu's back from being damaged, the exercise wheel should be no smaller than 13" in diameter.  In addition, the exercise wheel needs to have a solid surface in order to prevent the degu's toes or toenails from being caught in spaces which could result in injury or breaking of the toe or toenail.  Also, there needs to be no crossbar to avoid potentially fatally catching a degu's head or tail.  Finally, the exercise wheel should not be made from plastic, so the degus cannot chew it.  These instructions are for an exercise wheel that meets all of these requirements.  In addition, this exercise wheel (unlike an exercise wheel made with a lazy susan bearing) is silent.  As this exercise wheel is home-made, it is likely to be less expensive (although more time-consuming) than a purchased exercise wheel meeting all of the above requirements for an exercise wheel for degus.