Opticron original lens cap with rubber grommet suitable for binoculars with 80 mm objective (front lens) and outer diameter ~98 mm.
In the assortment, this is matched by the Opticron ES 80 and HR 80 models, but can also fit, for example, Celestron Regal M2 80 and other models. The suspension ring is flattened in height and can therefore be wedged between the tube body and the extendable anti-light and rain cover.