Product Features:Step 1: Mount 4 of the thumb-screws at 90 angles to each other like in the photo. Do not thread them in too far just yet.Step 2: Place the adapter ring on a flat surface with the groove down as shown.Step 3: Place your lens in the centre of the ring and screw in each thumb-screw until the lens is held tightly while taking care to make sure the lens remains centred. Some minor adjustments may be necessary based on the design of the built-in hood.Done Now you can attach the Cokin XL filter holder (sold separately) to the adapter ring and insert your XL series filters. 4 screws is usually enough to create a solid connection but depending on your lens and shooting conditions you may want to add more screws to increase stability between the system and your lens.The Cokin X499N Universal adapter is designed to mount onto lenses with built-in hoods between 75mm and 115mm in diameter. The Cokin Solution for Super-Wide LensesWe hear this question a lot, "How can I use a filter with a super wide-angle lens that has no filter threads?" The answer is simple, use the Cokin X499N Universal Adapter ring with the XL holder and filter system. The adapter has been tested to work with many of the popular super-wide lenses like the Nikon 14-24mm, Tokina 16-28mm, Canon 11-24mm, Tamron 15-30mm and many more. Let me take you through the set-up process to help you decide if this is the right solution for you.The X499N mounts on a lens without filter threads using 4-8 soft-tipped thumb screws that hold the adapter ring to the end of the lens. Once it is in place you will slide an XL filter holder onto the X499N Universal adapter ring. Note: The XL filter holder might vignette (block the very edges of the photo) when used with certain super wide-angle lenses at their widest focal lengths. Be sure to test for this before your first shoot.What's in the box:- Cokin Universal ring XL (X-PRO) Series- 8x Locking Screws