Precision battery hydrometer for testing the solution content in each cell. Graduations: – 0.005 g/ml; Red: – Ranges from 1.100 – 1.205. indicating the battery is discharged. White: – Ranges from 1.205 – 1.260. indicating that the battery requires attention. Green: – Ranges from 1.60 – 1.300. indicating the battery is fully charged. Calibrating should be carried out at 20 Deg C. Care must always be taken when removing battery cell caps and when testing. Manufactured with a glass tube, PVC bulb and spout.