The puck is made of vulcanized rubber, three inches in diameter and one inch thick. It weighs about six ounces. Speeds up to 120 MPH have been recorded by some of the hardest shooters. Compounding the problem for goaltenders is that frequently the puck will curve in flight, much like a baseball. Generally speaking, the most difficult shot is low, a few inches off the ice, to the stick side.
Some goaltenders overplay to the stick side, presenting a more inviting target on their glove side.
Many people think that deflections are mere luck. Actually, however, players practice on deflections constantly, standing off to the side of the nets, or in front, and deflecting the shot from outside to another area of the cage. Seldom does a goalie have time to react to a deflection as the puck changes direction off someone else's stick or skate. Not kicked in intentionally, but a puck can be deflected off a skate, or off a players' body if no overt attempt is made to throw it or kick it in. There is no goal.