Question about power adapter for 7500 vs 7900

[askew]

I recently got a LK-7500 and I want to purchase a second power adapter.

The only one I can find after a few minutes of looking is on Amazon: https://www.amazon.com/gp/B00D5696GA
I assume that this LK-7900 adapter would be compatible with the LK-7500 but I am concerned with the picture on Amazon. There is something in the middle of the wire that the LK-7500 power supply doesn't have. Pictures on the Lukas site and green-sum on Ebay are identical to the Amazon photo.

Does anyone know what the purpose of that device/connection in the middle of the wire is? Would the LK-7900 PS be fine for me to use on a 7500?

Thanks

 

[Gurkha9]

Could just be a ferrite core to reduce potential interference. Both use 12v on the input, doubt if there is any difference other than their rated temperature tolerance (7900 is higher)