If you really want to use products like a training mask, go ahead. HOWEVER, there are some things to keep in mind:
1. You do NOT need to spend money on products in order to maximize results
2. Training masks are generally for cardio workouts, so if you're following Chris's guide, the mask won't work as well.
3. You could buy a heck of a lot of other stuff with $60+.
If I were you, I'd spend that money on something else or save it. Getting a good and sufficient sleep every night, eating nutritious foods, maintaining a positive attitude, working in sunlight (as opposed to indoor fluorescent lights), working out at the time of day that suits your body best, and tons of other (free) things will increase your performance and growth more than a training mask ever could. If you still want to buy it, go ahead! Just don't expect to see any life-changing or incredible results if you do. :)