Seadog 211 "racing junior" clamcleat. All aluminum construction. Good for high load applications. This cleat is used throughout the Core Sound series for securing all control lines and halyards.
When used with halyards especially it should be paired with the "cleat keeper" CL-814, a black plastic cage that fits around the cleat and prevent the line from re-cleating once it has been released. This way you don't have to fight the cleat when trying to pull the sail down!
Works well for 3/16" and 1/4" line.