The TC (to contain) feature of this pipet accommodates use with viscous liquids, where the entire contents are washed out. Calibrated "to contain" (bottom line) and "to deliver" (top line) to Class A tolerances. Color code. Unserialized. Designed and manufactured to ASTM E969 requirements. Manufactured from 51 expansion borosilicate glass conforming to USP Type I and ASTM E438, Type I, Class B requirements.