Check the listing for details. 2.750" plate with ridge 4 Sigma APO Macro 180mm F2.8 EX DG OS HSM Kirk RRS Arca. Condition: New. Listed at 42.00 USD. Part Number # C1-275Product Description:New Hejnar Photo Quick Release 2.750 inch rail with ridge for Sigma APO Macro 180mm F2.8 EX DG OS HSM All single mounting hole lenses required anti twisting ridge to prevent lens rotating when mounted. It is the best quick release system for tripods and monopods when combined with Arca style ball head and quick release clamps. International standard dove-tail rail, compatible with Arca-Swiss type quick release clamps. Compatible with:Markins including level release clampReally Right Stuff, including level release plate.Arca SwissWimberleyKirkPhoto ClamFoba Vanguard ABH Series Ball Heads (ABH is Vangaurds only Arca-Compatible series)Custom BracketsJobu DesignsAcratechOther Arca swiss type products Specification:2.750 inch long1.5 inch wide3/8 inch thick plus 1/8 ridge height.Weight 41g (1.4oz)One captive style slot.Double-dovetail design allows for dual clamping surfaces on railTwo safety stops. This prevents free fall when the clamp is not fully closed. (M3 screws)Precision C.N.C. machined from 6061-T6 AluminumStainless steel hardware.Made in USABlack Anodized. Auction Includes:One 2.750 inch plate.One 1/4-20 ½ inch captive style screw.Two M3 screws attached to the plate.Hex key for ¼-20 screw and M3 screw Shipping Information:Free Shipping with USPS First Class Mail. Tracking information provided. USA Costumers please note that USPS packages may travel much longer than the estimated delivery time and tracking information is not always updated daily. If your order is time sensitive, you need daily tracking update please use FedEx, UPS or Express Mail as delivery service during checkout.