Rob Allen Whitetip Snorkel Size:OS The ultra durable 4 way stretch HYDRAFUSE™ 840447700244 The ultra durable 4 way stretch HYDRAFUSE™ SCRAPEarmor™ fabric on the knees and reliability The Rob Allen Whitetip Snorkel features a large bore for ease of breathing during repetitive dives and because it is completely flexible in the bore it stops dangerous snagging issues with float lines or rigging The softer semi rigid design of the snorkel bore also increases the streamlined hydrodynamic design of the snorkel in the water and eliminates that annoying banging against your head characteristic that similar products are renowned for