Amazon.com: 9v Battery Eliminator (9v DC Adapter & Battery Eliminator) - Replace Your 9-Volt Batteries with Wall Power Supply : Electronics
Connector for 9V battery
9V Battery Connector to Standard Male DC Plug 5.5x2.1 mm Jack Snap T Type Buckle Power Adapter Adaptor Arduino 9 V Cable Wire | Lazada PH
9 V Battery Clip Connector, I-Type 9 Volt Battery Clip, 9V Battery Buckle Connector Hard Buckle Plastic Housing and Black Red Wires Leads Iength 5.9 inches (I Type Hard Shell 8PCS) :