The Dovetail Plates are the heart of the Losmandy Secondary System. 0.5 inch x 4.0 inches x length of the tube assembly. Dovetail plates may be mounted to the top and bottom of tube assembly for mounting of all D series accessories, making it possible to use both sides of tube for equipment. The dovetail plates, like all accessories in the Losmandy line, are machined for lightness and rigidity from aluminum stock, then black anodized for a tough, corrosion free surface. Celestron dovetail plate for 11 inches, bolts to existing holes. Includes curved blocks for precision fit to the tube assembly. Wt. 2.25 lbs. Length 17.25 inches HS 16.0/16.50 Ht. top of tube to top of dovetail plate 1.00 inch Thickness .6 inch