GB/T 2 2055.2 - 2 0 0 8 is the second part of the Microscope objective thread standard, focusing on the M25 × 0.75mm objective thread. In the Microscope system, the accuracy of the objective thread determines the installation effect and overall performance of the objective lens. This standard specifies the key indicators of the M25 × 0.75mm objective thread, including thread outer diameter, inner diameter, pitch and other dimensional parameters and tolerance ranges. Provide a unified specification for Microscope manufacturers and objective manufacturers to ensure that this type of objective lens and Microscope fit well, achieve stable connection, and ensure clear Microscope imagery and smooth operation.