This Snorkelling set from Mares is an adult set made from tempered glass,100% silicone, making this extremely good quality. The Mares Cobia mask is super comfortable and has an easily adjustable strap. Being silicone, this will last many years, being cleaned properly after every use. The snorkel in this set is also made from silicone and has a comfortable mouthpiece. With a purge valve at the bottom to allow water to be blown out and a wash over on the top to minimize water getting in.