[replacement]:directly replaces your worn,cracked,broken,and unusable rail bar mounting plate [simple installation]:telescope dovetail mounting plate,easy to replace and install within seconds,no complicated tools needed [material]:the dovetail mounting fixing plate is made of premium aluminum alloy material,wear resistant,and has good performance [product size]:the telescope dovetail mounting plate length is 30 cm/11.81 inch [multiuse]:this dovetail plate can be used for astronomical telescopes,connected to other equipment,professional and practical