Durasight One Piece Ring Base System Medium Fits Post 2010 CVA by CVA Product Overview now offers the CVA Durabright One Piece Ring Base System and Medium Profile. The One Piece Base is a low profile style scope mount and will fit CVA firearms manufactured after 2010. The One Piece Base is durable and built to last. The rings are securely locked with two screws on each. The Medium profile allows for a good sight picture and proper eye relief for your favorite scope. Specifications and Features: Medium Profile Durable Construction Fits All CVA Firearms made after 2010