A: To achieve a sealed installation of the lens assembly, when sealing is required between the front/rear flanges or the lens-module interface, proceed as follows: Apply a thin, uniform layer of silicone-based lubricant to the surface of an O-ring matching the original specifications. Using precision tweezers, carefully position the O-ring along the circumferential path of the sealing groove and gradually seat it into the channel. Ensure complete circumferential engagement with no localized protrusions or depressions within the groove. Verify full seating integrity prior to proceeding with final assembly of the sealed components.