Players must wear eye protection according to U.S. Lacrosse rules. All field players must properly wear eye protection that meets ASTM specification standard F803 for women's adult/ youth lacrosse for the appropriate level of play. All players must wear a professionally manufactured intra-oral mouthpiece that fully covers the teeth. The mouthguard must include portions protecting and separating the biting surfaces and protecting the teeth and supporting structures and has to cover the posterior teeth with adequate thickness. Most referees do not allow mouth guards to be white or clear colored as it is too difficult for them to distinguish between the mouth guard and the player's teeth. Mouth pieces must be worn at all times and cannot be taken out in the middle of play. No protruding tabs are allowed for field players.