Special mounting screw for use only with Barska(TM) binoculars. (Caution: Will not work with most binoculars) Purchase additional mounting screws to use multiple binoculars with a single FAR-Sight bracket. (A single FAR-Sight Standard Binocular Mounting Screw is included with the purchase of FAR-Sight.) The Barska(TM) Binocular Mounting Screw is for binoculars which have a non-standard 1/4-inch x 28 threads per inch mounting hole. (Most binoculars use this configuration.)