8x57 I have e-mailed Leupold regarding a replacement, bewsher 500, its a small 19mm long bar shaped to sit in the base of the mount its held in place by the sides of the mount that grips the Picatinny rail , problem is when the base is opened to fit onto the rail they can drop out , I did think of gluing them in with a spot of superglue but not sure if they are designed to "float" about, I've just made a replacement out of aluminium should do until I get a Pucka one.