This lens cap is for optical instrument (eg. binoculars, telescopes and spotting scopes) and accessories (eg. eyepieces, Barlow lenses).
Internal Diameter: 40mm
(Note: this is measured as internal diameter of the cap, which is equivalent to the external diameter of the lens including the lens housing).
Depth: 11mm
Material: Rubber
Note: This listing is for ONE lens cap as described above (not for a pair). The cap is made of rubber material which is flexible. For this feature, the cap can normally accommodate lenses with slightly bigger diameters. For example. this cap can cover lenses with external diameter around 40-41mm.
Note: The size of the lens cap is measured as Internal Diameter of the cap, which is equivalent to the external diameter of the lens including lens housing (as shown in the picture above). Please allow a small difference in measurement (eg. 0.5-1mm). A rubber cap can normally fit a slightly bigger lens than the specified size (eg. +1mm to 2mm depending on actual size).
If a cap is slightly bigger than the external diameter of the lens housing and there is no matched cap size available for the lens, you may consider putting an adhesive cloth tape around the internal edge/rim of the cap. This can often secure the cap on the lens.
