[OBJECTIVE LENS SET] This set includes a range of magnifications 4X, , 20X, 40X, 60X, and 100X, suitable for various microscopic applications. [PROTECTIVE SPRING LOADING] The spring-loaded mechanism on the 40x, 60x, and 100x objectives protects your slides from potential damage during examination. [OPTIMIZED FOR ] Coated optical parts provide enhanced visibility and minimized distortion, clear imaging in all conditions. [ADVANCED NUMERICAL APERTURE] Featuring a unique design in the 100x objective that utilizes pine pitch for improved performance in high-resolution imaging. [SIZING REMINDER] you check your own size specifications rather than relying solely on standard charts.