Ultimate dog trainer is a great app to assist you in training your pet, it is design to emit a high frequency sound that will get the attention of your pet.
Or can be used as a corrective method.
Please note that this app is not meant to hurt animals in any way it´s just meant to assit you in their training please use it with responsibility.
Note: is recommended to use it with new Ipod and Ipod touch models (3G and Up) you can also use it with an external speaker to maximize efficiency.