Coverslip thickness

Number Ideal thickness Range
#0 100 μm 80-130 μm
#1 150 μm 130-170 μm
#1.5 170 μm 160-190 μm
#2.0 220 μm 190-250 μm

Most objectives are designed to use #1.5 coverslips. Using the wrong one may have serious implications for image instensity and quality. This is particularly true for objectives with NA above 0.4 and when the sample is very close (eg adhered to) the coverslip. There is actually a surprising amount of variation in a batch of coverslips. If your application is very sensitive to coverslip thickness you can measure them and use the ones close the ideal value.