Choosing the right battery

[Elefantenpogo]

Hi guys,
I already searched the forums for the topic and founds some posts, but none of them really made me happy.
Here's the problem: I'm from Germany. The recommended LiPo from Adafruit is, thus, not really an option, as the shipping costs would be way to high. On my journey to find an alternative, I came up to those ones:
https://eckstein-shop.de/LiPo-Akku-Lith ... -Connector
-> perfect size (58,5mm x 34mm x 5mm), but just 1100mAh. Not sure, if the difference between 1200mAh and 1100mAh would be really that great.

https://www.amazon.de/dp/B003TRTYBC/_en ... X5GB31DC5K
-> should fit (60mm x 36mm x 5mm), 1250mAh but not sure, what the yellow cable is doing and what it will be doing, if I just ignore it, using only the red and black one.

In addition, I found some "perfect" batterys from some chinese Ebay-Stores, but honestly I don't want to risk building some sort of expoldingPi.
Maybe you can make some suggestions to the two ones above or give some tips, which battery to use.

Thanks in advance.

[Kloper]

I used similar to the second one. It's for Garmin navigation devices. It's a tight fit, but fits. Plus it's a bonus that I can buy those in local electronics shop. And yes, you just ignore that green wire (in my case). I securely taped it to the side of the battery and used only red and black.