Whether it's your clumsy friend or an excited pet, breaking a downstem is annoying and inevitable. Always have a backup to keep your session going with this two-pack of replacement downstems. ** Note: This product is only for the Session Bong. Session Downstems Features: Clear Borosilicate Glass Joint Size: 10mm | 0.39” Downstem Width: 16mm | 0.63” Tri-Slot Diffusion for Smooth Hits Designed to Fit the Session Bong