Manufacturer: drut. 5.5mm x 2.1mm DC In Line Socket to 3.5mm x 1.3mm DC Jack Plug Cable Converter. connector sizes. With a 5.5mm x 2.1mm DC socket on one end and a 3.5mm x 1.3mm. Secure and Stable Connection: The adapter features a secure 5.5mm x 2.1mm DC socket and a snug-fitting 3.5mm x 1.3mm DC jack plug, ensuring a stable and dependable connection.