Amazon.co.jp: 2.5mm 0.7mm DC Converter Adapter Plug Set of 5 wuernine Outer Diameter 5.5mm Inner Diameter 2.1mm Female to Outer Diameter 2.5mm Inner Diameter 0.7mm Male for Power Supply : Electronics
LUM 1636-01: DC power plug, straight, Øi = 0.7 mm, Øa = 2.35 mm, JS at reichelt elektronik
Switch Electronics 0.7mm x 2.5mm Male DC Power Plug Jack Connector (Pack of 5): Amazon.co.uk: Electronics & Photo
Dc Power Plug Connector 1.7 | Connectors Power Supplies | Power Connector Adapter - Connectors - Aliexpress