The CA-15 was designed in part by an ex-Canadian military officer and a professional gun smith for flat top and bolt action precision rifles. It is uniquely a combination of traditional 2" and 3" cantilever scope mounts and is precisely adjustable for ring spacing and placement. It is "four lug" design. It is machined on Vancouver Island from 7075 aluminum and 4140 HTSR steel. Each scope mount undergoes careful assembly and inspection prior to shipping, one mount at a time. Price includes tax and shipping. To order or to discuss in detail, call direct on Pacific Standard Time. EMT only. Thank-you.