Protection: Yes, Product name: XTAR 26650 5000mAh Li-ion Battery, Capacity: 5000mAh, Voltage: 3.6v 18Whh, Size: 69.2mm(length).
Check coupons or create price alert down below. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($15.17): BGAlerabat15
2. ($16.06): BGtorch2
just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): 00c906, BGtorch3
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for XTAR 26650 5000mAh 3.6V Protected Battery. The lowest price was: $13.79.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).