Seriously, I would save my money. Have you done much obedience work in the yard? Here is a good one for retrievers and flushing dogs (not sure if pointer guys want there dogs to sit in the field or not) when you are training in the yard and tell your dog to sit at a distance and he doesn't, lead him to where he was when you gave him the command, make him sit, go back to where you were when you gave the original command, make him keep sitting and then release him. Start when he is close to you and eventually move further away as he gets better. Then take him to the field and do the same thing (start close and then make him obey further and further away). I use treats to reinforce this stuff in the yard (when he does what you want walk out and give him a treat and go back to where you were standing and release him. For some dogs a treat can just be a pat on the head, for others it can be a piece of kibble). Do this exercize a couple of times a day for 5-10 mins a session and your dog will respond better to you in the field.
Another good one= Go to youtube and look for the 'touch' command for a strating place to teach your dog to retrieve to hand.
I hope this helps,
Rick