Griffco Borosilicate Glass Calibration Cylinders are designed to enhance the performance of chemical feed systems by providing a verification of the flow rate of the chemical feed pump. Constructed of borosilicate glass and a choice of 5 end cap materials, (PVC, PTFE, PVDF, 316 SS, A20) these cylinders are suitable for use with most chemicals. 6 sizes; 100 mL, 200 mL, 500 mL, 1000 mL, 2000 mL, 4000 mL.