Great Tips! Before you even begin swimming with the snorkel, just place your face in the water and breathethrough the snorkel to get comfortable. Ensure that you have a good seal around the mouthpiece. You do notwant your mouth to be too relaxed as it may let water in the tube however you do not want to bite down toohard on the mouthpiece as this will wear the mouthpiece faster than normal.Specification:Material: Silica gelSize: Length: 45cm/17.7''Color: YellowFeature:Center-mount Design: Relax in the water in order to focus on stroke and improve technique.One-way Purge Valve: Allows for clear and easy breathing.Adjustable Head Bracket: Can be worn in conjunction with swim cap or goggles.Hydrodynamic Design: Worn with swim goggles, promotes proper head and body position.Front Positioning: Swim at slower speeds with perfect stability.Silicone Mouth Piece: Soft, comfortable, flexible medical grade silicone.Notice:1.Please allow 1-3cm error due tomanualmeasurement.Pls make sure you do not mind before you bid.2.The color may have different as the difference display,pls understand.