The label TD on a pipet refers to its intended action.

• A. To drain
• B. To deliver
• C. To calibrate
• D. To sample

Answer: (B)

The key idea is what TD tells you about how the pipette works. TD means “to deliver,” so this pipette is calibrated to deliver the set volume into the receiving vessel when you use the first stop on the plunger. It may leave a tiny amount of liquid in the tip after delivery, but the stated volume is what’s delivered. This is different from “to contain” (TC), where the full drawn volume is only delivered when you blow out with the second stop.

So the label indicates the intended action is to deliver the measured amount, not to drain the tip, calibrate it yourself, or sample differently.