Description of Sigma Electric ProConnex TC 502 Connector
Terminates 3/4-in EMT conduit to a 3/4-in knockout in an outlet box or enclosure. Set screw type with a tri-combo screw. Concrete-tight when taped and for dry location applications. Zinc die-cast construction. Product is UL and CSA listed.
Although the container was labeled as a 3/4" EMT connection, the product is designed for a 1/2" EMT connection. I suspect it's just a mislabeling issue.