They have been designed specifically for live cell imaging procedures and calculated for certain temperature ranges.Different refractive indices, arising in live cell imaging due to temperature changes in the sample or the immersion medium (e.g. bydeliberately heating the sample), would impair the imaging quality of an objective. With just a single correction ring it is possible tocompensate for refractive index mismatches.The correction ring has the following markings:Setting of the refractive index for the immersion media water and glycerin, a marking for use with or without cover glass and also, onthe LCI 63x, a marking for the temperatures 23° and 37° Celsius (the temperature impact does not play a visible role on the LCI 25x