Why do defenders wear face masks at penalty corners, and how long is the wait?

All field players defending a penalty corner must wear a face mask until the first shot at goal. If a defending field player removes the mask before that first shot, the penalty corner is re-taken.

When an initial penalty corner is awarded, match time stops for up to 40 seconds so defenders can put on protective equipment. For a re-awarded corner, time stops immediately but no extra 40 seconds is given. The umpire advises both teams as the countdown clock nears zero and restarts play no later than after 40 seconds if both teams are ready.

If a team is not ready, the umpire decides whether the delay was players finding and putting on their protective equipment (extra time is allowed without penalty) or intentional (a green card for the player concerned, and a yellow card for repeated offences). If a defending player caused the delay, the defending team defends the corner with one fewer player.