Classic J-Tube design Easy Breathing Simple Comfortable Great for Freediving Be a part of the Evolution. Simple, comfortable, and effective. The Hammerhead Spearguns Classic "J" snorkel has a semi-soft tube and silicone mouth piece for comfort and durability with a high vis marker top. Evolution "J" is the perfect compliment for the Hammerhead Spearguns MV series of masks. Compatible with any mask. Simple yet effective, economical with a easy breathing wide bore airway.