Ruger Standard, Ring, 30mm High(5), Matte Blue Finish, 5B30HM, Sold Individually 90322
Specifications:

Type	Ring Single
Tube Diameter	30mm
Height	High
Size	Accepts up to 52mm
Finish	Blued
Style
Material	Alloy
Style Description
One or Two Piece	1
Adaptor Type
Mount Type
Lock Type