Perfect fitting and anti-leakthis kid swim mask is perfect fitting for kids ranges from 3-12 years old.Please kindly tighten the mask by pulling the strap and ensure the silicone skirt fully absorbed on your face,then it ensures that no water will leak in while swimming,snorkeling and scuba diving .So please confirm whether you have tightened the strap sufficiently while using the snorkeling goggles. Silicone Nose GogglesAnti-fog Tempered Glass Lensthis snorkel mask is with nose cover ,which is perfect for users who do not know how to stop breathing by nose when swimming,snorkeling or scuba diving.Lens of our kid dive masks are made by tempered glass,which is more durable and thicker than normal swimming goggles with plastic lens,can hold water pressure and be anti-fog when swim or diving deeply. Food grade non-toxic materialStrap and skirt of kids scuba mask and mouthpiece of kids diving snorkel are made by super stretchy food grade silicone,which is scentless and can be used for a long time without changing the color and structure. The healthy silicone material makes kids feel comfortable and happy.