4T Pro comes in CR2032 and AAA battery (4XT Pro) versions, +/- buttons on top and a night vision button. 4T only takes CR2032 and has solar panel on top with +/- buttons on the left side.
4T also comes in two reticle flavors, the 2MOA circle dot and a 1MOA CirclePlex. The 2MOA is vastly more popular and same as the reticle in the 4T Pro. The CirclePlex version were always cheaper and less popular.
4T has a dark semi-gloss black finish and the 4T Pro is more of a matte finish.