This 4.75-inch long glass diffuser downstem features a 18.8mm male to 14.5mm female joint connection, making it compatible with 18.8mm female-jointed water pipes. 

Whether you broke or misplaced the original 4.75-inch long downstem that came with your bong, or simply want a spare, this diffuser downstem will serve you well for a long time. It features a classic 6-cut style found on most bongs for smoothing and filtering your hits.