This 2 piece screw & marble terp bead set includes a large marble carb cap and a screw style flow bead that is perfect for use with the Terp Slurp Banger. Terp beads assist by stirring concentrates via airflow or regulating airflow as a marble cap. Includes reusable plastic container (2.25" diameter). Colors vary Approximate bead sizes: 23.75mm marble diameter & 26mm x 14mm screw dimensions