The Opticron Rubber Objective Lens Covers for Outer Diameter 50-51mm are designed to protect your binoculars’ objective lenses from damage caused by impact, water, and dirt during transit or storage. These covers are made of durable rubber and fit snugly over tubes with an outer diameter of 50-51mm, ensuring a secure, friction fit. They are easily removable when needed, providing quick access to your lenses. While offering excellent protection from dust and dirt, the covers remain attached to the instrument when in use, making them a convenient and reliable accessory for your binoculars.