"The Lens Mount Cap provides better protection to the lens mount area. It is designed with an O-ring seal which creates a positive contact with the full perimeter of the lens mount area to really lock out dust and moisture. The Lens Mount Cap from OP/TECH USA is available in sizes to fit today's most popular mirrorless camera lenses as well as DSLRs. It's sure to be a hit with both amateur and pro photographers. It's no ordinary cap... the benefits and versatility are sure to please. It's designed with an O-ring seal which creates a positive contact with the full perimeter of the lens mount area to really lock out dust and moisture. It also offers a tighter friction fit over traditional caps that come with the lens so that it provides better protection to the lens mount area. This ensures that the Lens Mount Cap is securely held in place while in storage or transit. The Lens Mount Cap is available in single or double versions in several lens models for both D-SLR and Mirrorless cameras. The double version is a huge space saver as it enables the photographer to safely and securely lock two lenses together. Keeping gear protected in a compact fashion really helps the active photographer organize and plan for their next photo adventure. By using the Double Lens Mount Cap on a single lens, you can change lenses faster than ever! Remove the lens from your camera and immediately apply it to the open end of the double Lens Mount Cap. Then simply remove the other lens|Provides increased protection over traditional covers|Unique O-ring seal locks out dust and moisture|Available in single (one lens) and double versions (holds two lenses together)|Available for DSLR in Canon, Leica M, Maxxum/Sony, Nikon, and Pentax lens versions and for Mirrorless in Fuji X, Olympus/Panasonic MFT, and Sony E lens versions|Made of hard plastic|No need to find your size, just choose your lens brand|Made in the USA"