Power adapter barrel connector size?!?

Hello we have a bunch of 10.1’’ 1280x800HDMI Touchscreen for Raspberry Pi/LattePanda/Beagle Bone/Libre Computer Board’s (SKU: CN0405) and I’m wondering what the barrel connector size is for the power supply?

Thank you for your time and effort!

The DC plug size for the power adapter is:5.5mm x 2.1mm