Freestyle is one of the fastest swimming strokes and by decreasing your body's resistance to water, you will swim faster through water. 

You will benefit  a lot in using frontal swimming snorkel for freestyle training .

The benefits of the frontal snorkel for the swimmer will be:

 1) Gain a stable and relaxed body position in water.

 2) Less resistance and physical stress on the opposite side of the body, since there is no

     need to breath sideway.

 3) Encourage swimmer to kick from the hips rather than kicking from the knees.

 4) Increased swimmer's breathing capacity. Designed for use with conventional swimming

     goggles and silicone swimming caps.