Check Second picture to see the visual difference between 2.1mm and 2.5mm Pin thickness
Options with cover added, where they fully fit.
Cover plug will fit all 5.5mm holes, but sealing ring is for 12mm and wont seal small sizes like 7 or 8mm.
If your application require high currents, my suggestion is to use 2.5mm inner pin and the all Copper 11mm socket or the other copper sockets. With 2.5mm pin, you will need plug 2.5mm (hole), which is not the most common.
Options Description:
5.5x2.1mm Mini 8mm / 5.5x2.5mm Mini 8mm
Mounting Hole: 8mm
Overall size: F10x18mm
Comes with Nut
All nickel plated copper, except the nut
5.5x2.1mm 8mm / 5.5x2.5mm 8mm
Mounting Hole: 8mm
Overall size: F10.5x21mm
Comes with Nut
All nickel plated copper, except the nut
5.5x2.1mm 11mm / 5.5x2.5mm 11mm
Mounting Hole: 11mm
Overall size: F12.5x27mm
Comes with Nut and Washer
All nickel plated copper, except the nut and the washer
5.5x2.1mm 12mm / 5.5x2.5mm 12mm / 5.5x2.1mm 12mm WHITE
Mounting Hole: 12mm
Overall size: F14x18mm
Comes with Nut
5.5x2.1mm PCB Type / 5.5x2.5mm PCB Type
Mounting Hole: 9x11mm
Overall size: 9x14x15mm
5.5x2.1mm Ears / 5.5x2.5mm Ears
Mounting Hole: 9x11.5mm
Overall size: 9x20x17mm
Screw Spacing:15mm
5.5x2.1mm Square / 5.5x2.5mm Square
Mounting Hole: 13x11mm (the slot size)
Overall size: 13x15x19mm
Slot is 2.2mm wide
3.5x1.35mm (1.3mm) PCB
Mounting Hole: 5x7.6mm
Overall size: 5x10.7x11.5mm
Good for low current, low voltage applications.
That size is usually used for 5V and it is not possible to plug 12V plug, by mistake, which is the point.
6mm Plug/12mm Ring Cover
Cap is 5.8-6mm PVC rubber and will seal almost any 5.5 opening
Sealing ring is about 11-12mm (inside) and will stretch to 13mm.