The LEOK-3 Optics Experiment Kit is developed for general physics education at universities and colleges. It provides a complete set of optical and mechanical components as well as light sources. Almost all optics experiments required in general physics education (e.g. geometrical, physical, and modern optics) can be constructed in sequence using these components. Through selecting and assembling corresponding components into setups, students can enhance their experimental skills and problem solving ability. The instruction manual contains comprehensive materials including experiment setups, principles, procedures and required parts with photos. LEOK-3 shows a total of 26 experiment examples which are grouped in six categories: 1.Lens Measurements: Understand and verify lens equation and optical rays transformation. 2.Optical Instruments: Understand the principle and operation of common lab optical instruments. 3.Interference Phenomena: Understand interference theory, observe various interference patterns generated by different sources, and learn one precise measurement method based on optical interference. 4.Diffraction Phenomena: Understand diffraction effects, observe diffraction patterns by different apertures. 5.Analysis of Polarization: Understand polarization and verify types of polarized light. 6.Fourier Optics and Holography: Understand principles of advanced optics and their applications.