a crate locking device for holding plastic storage crates together making a solid storage unit . the crate locking device has a dove - tail configured protuberances along its outer periphery . the dove - tail protuberances are evenly spaced along the four sides such that opposing sides are reversed mirror images of each other . two adjacent dove - tail protuberances are spaced from each other to receive a dove - tail protuberance from an adjacent crate locking device . the dove - tail configuration prevents lateral movement of adjacent crate locking devices relative to each other .