Accurately measures the strength of battery fluid, screenwash, antifreeze and AdBlue® by measuring the refractive index of light passing through the mixture. Suitable for synthetic antifreeze mixtures including long life OAT (Organic Acid Technology) and aqueous/urea content of AdBlue®. Temperature corrected prism ensures accuracy. Eyepiece with adjustable focus. Simple calibration check using distilled water. Supplied with pipette and carry-case.