Product Description David Clark C31-25 Straight Cord - Number After Dash in Model Number Indicates Length in Feet. Features 1/4" TRS plug and mating jack Models available from 12 to 100 feet: C31-12, C31-25, C31-50, C31-100 Designed for use with Series 3000 headsets 25 foot Straight Cord with (SC-838) Female Connector and (PJ-051) Plug