The 77mm Iris Lens Cap from Holdland lets you protect your lens without the hassle of other conventional lens caps. When you're ready to shoot, simply twist the outside diameter to open the iris, and expose the front element of your lens, and when you're done, twist it back to close for maximum protection. This lens cap with its intuitive design and durable titanium-coated steel construction is great for photographers working in the elements who need an extra layer of security and convenience to get the most out of their gear.