Warnings:1. The snorkeling mask is for snorkeling only, please don't dive into free diving,scuba diving or strenuous swimming.2.Not suitable for children under 14 years and must be strictly under parent supervision only .3. Just leave it dry naturally after cleaning mask with fresh water to avoid direct sunlight and use glasses cloth to clean the face lens, don't use towel.Specification:Size: S / M, L / XLSuitable for: adultsColor: red and black, pink, gray, green, red, black, blueMeasure the length from the eyes to the chin:If the length is less than 5.1 inches, please choose S/M.If "Length is equal to or greater than 5.1 inches", please select "L/XL".Package Included:1x Full face snorkeling mask1 mesh bag (dry the mask)1x earplug set1 screw1x rubber ring1x manualFull Face Snorkel Mask|Easy Breathing Snorkeling Mask| Swimming Diving MaskHow To Wear Snorkel Mask:1. Install the breathing tube on the snorkel mask.2. Install the removable action camera mount on the tube, then fix the camera tightly on the mount.3. Put on the mask and adjust the length of the elastic bands, please make sure there is no gap between the mask and your face.What size should I choose for snorkel mask ?Step 1. Measure the distance between the bridge of your nose and the bottom of your chin.Step 2. If the distance is 8-12cm, choose XS.If the distance is 10-12cm, choose S/M.If the distance is 12-14, choose Large/XL.