DC Adapter - 2.1mm Female to 2.5mm Male

Allows a 2.1mm DC jack plug to be used in a 2.5mm socket Allows you to make use of your spare AC Adapters Connectors: 2.1mm Female (3.5mm outer diameter) to 2.5mm Male (5.5mm outer diameter)

Price: 1.82 from Boxed2me