1X46T red dot sight has integrated mount that is adjustable to accommodate both the Weaver base or 7/8" dovetail base you have available. Simply reverse the side rails to fit onto the specific base you have. The sight has a more visible Green/Red "T" dot needed for faster target acquisition. Objective Size: 46mm. Overall Length: 3 7/8". Uses one CR2032 Button Cell Battery(included). Flip-open lens covers included.