When young kids get scammed they stay silent, no one should know that they did wasted one hard earned dollar or Euro Coin, and they go an unusable gadget.
Even so the Chinese home factory, it did get paid, among the eBay seller and everyone in the chain including banking system.
My GOLDEN advice always resize to real dimensions every product oversized picture, this is the only indication of what its product this is made of.
In the specific gadget, the unseen (covered scam) this is the build quality of the Alligator Clip that is totally unusable.
Additionally the not mentioned scam this is relative to wires thickness.
Lastly the BNC connector this is nothing special either, current handling this is at 2~3 A Max.
In conclusion this is a toy level gadget 100% unusable as is.
If you think to replace wires and alligator clips with better ones ? Then the magic of such purchase this is vanish.
My advice if you need cables to test a USB power bank? This is getting all parts you need one by one, and make the Assembly by your hands.
Only then you can feel confident that your testing wire this is not a toy.
I just lost 0.70 EUR for educational purposes, DO NOT follow this path.