The Metalab Cyprium Solid Medium Port 16 MM Weymouth is designed with a solid, 16 mm mouthpiece that has a medium port. The Bottom CP is 2 3/4". Cyprium-90 is a hi-tech alloy which contains a minimum of 86% of copper improving saliva secretion and 2% iron. Guaranteed free of nickel and zinc. The Cyprium-90 Metalab bits are long lasting and of very high quality.