The K&F Concept Insta 360 X4 Camera Battery Bundle with Charger is a MUST HAVE for those looking for some affordable battery replacements for their Insta360 X4. At the cost of less than one OEM Insta360 battery, you are provided with not one, but TWO higher capacity batteries along with a nice compact charger and USB-A to USB-C cable for charging. Build quality is nice and seemingly more rugged and a bit improved over the originals, with metal battery release prongs instead of the plastic ones that the original OEM batteries are made with. The rubberized water-tight seal is evident on both replacement batteries and they both fit nice and snug in the battery compartment of the X4. Capacity shows 2350mAh for the K&F batteries vs the 2290mAh on the originals. Basically 60mAh higher, although not sure how much longer it will power the camera vs the original. When snapped into the camera, the batteries both came showing that they were pre-charged at the factory, with just over 60% power remaining. Will have to see whether the battery capacity continues to retain nominal charge once I have more extensive use with these batteries. In the meantime, having the charger available to keep spare batteries charged is great instead of having to charge the batteries in the camera; allowing for extended use of the camera when needed. Surprisingly, the weight of the K&F batteries were seemingly a touch lighter than the OEM battery so I’ll have to keep an eye on whether the battery capacity is truly as stated. For now, I’m happy with the bundle as it allows me to go on trips without having to worry about running out of battery power at inopportune times. Again, for the cost of less than one OEM battery, you get two spare batteries AND a charger so this is a no brainer. Two thumbs way up for the K&F Concept battery bundle. Definitely a good purchase for your X4 camera!