Of all the training exercises to teach your dog, none are as important as a reliable recall. A recall enables you to keep your dog safe by bringing him close to you in unpredictable or potentially dangerous environments. Besides safety, a recall will also help you be more successful in virtually all areas of canine competition.
I purchased one of your Bob-A-Lots. Don't ever take it off the market. It is wonderful. Especially for those dogs that inhale their food and there is no other way to slow their eating. They get more bang for the buck if they have to work for their meal. Far more satisfying and better for their stomach.