Vinyl Mouth Guards with Strap - Youth (25-Pack) Mouthguards should be used in contact and non-contact sports to reduce the risk of concussion and mouth related injuries. The thickness of a mouthguard determines its effectiveness. The thickness of the cushion between the upper and lower jaw is the critical criteria in purchasing a mouthguard. Junior size for youth 10 years and younger. 25 per pack. Made in the USA.