Default Mpj Optimus 4x p880 slim battery a little higher than stock

I poked around looking for battery of LG Optimus 4x p880 and there are some with same dimension but higher capacity. The one I bought from mpj required my phone drained till it died and then charge to 100% (repeat several times). It REALLY a little bigger than my stock! Some days I get 40+ hrs of use out of my device. Surely it has shorter life as they have claimed, but I don't care. All I know it has getting better.