The V.4 is slightly more reflective than the basic T520 display. The B156HW01 V.4 on the left makes a more focused reflection of the overhead light while the stock display (LG LP156WH4) creates a larger diffused reflection.

The manufacturer of this panel is AU Optronics, a multibillion dollar Taiwanese company that specializes in TFT LCD technology. Lenovo uses AUO displays but LCD resellers are also able to get boxes of panels that are sold for DIY upgrades and repairs.