This whip tube mouthpiece kit is widely used for water bongs, dab rigs, pipe and other glass attachments.  There are two versions, the 18mm male version or the 10/14/18mm 3 in 1 version.  

Package contents

• 5 feet whip (about 1.5m length)
• glass tubing mouthpiece 
• 18mm male joint glass adapter  or  10/14/18mm glass adapter