Heavy Duty Material: The frame and stem are made of Selected CNC Billet Aluminum, ball socket is made of Stainless steel. You can touch and feel the quality material once you’ve got it. Much more sturdy and fashion. 3.5″x3.5″ mirror surface. R1200 Mirror, mirror glass for an extended field of vision. Note 1: Fits inside handlebars with 13 to 18mm inside diameters. Or (for reference only) ALL 7/8″ handlebar, Or 28mm inside diameters handlebar, please check the handlebars inside diameters. Note 2: Clarity is great and even has the slight blue tint to reduce glare and protect your eyes, the mirror provides you a wide view behind you, the mirrors should be installed on motorcycle handlebar. Installation: Three different thickness of black plastic sleeves to meet your purposes. If you have any issue on the installation or other issues on the mirrors, please do not hesitate to contact us. Please kindly try your best to tighten three strews(even though the screw exceed two threads), then the