Roor products are manufactured in Germany and are always made of a high quality and durable glass. These diffuser downstems are made of lab-created borosilicate glass that is extremely heat and scratch resistant. The 13 hole diffusor downstem gets its name from tiny holes in the end of the downstem. This provides maximum filtration of your smoke through the water which cools it faster and more effectively and prevents anything but smoke from reaching your mouth. Each Roor 13 Hole Diffused Downstem comes in your choice of lengths for your Straight neck pieces (7.75″ long) or Beakers (8.5″ long) and they fit 18mm bowls. So go ahead and grab one up as a replacement or the ultimate upgrade! These glass pieces are handmade to order, please allow 3-6 weeks for delivery. Looking for a 14mm downstem? Check out the Roor 13 Hole 14mm Diffusor.