From the Tamiya website:
The M26 Pershing, the first American tank capable of taking on the German Army's Tiger I and Panther tanks, was introduced during the final stages of WWII. The T26E4 was a development of the M26 and was armed with an even more powerful, long-barreled 90mm main gun. This gun was superior to the one found on the King Tiger heavy tank and could penetrate a Panther's frontal armor from long distances. The first T26E4 was sent to the European front in 1945, with subsequent examples featuring various improvements such as a modified gun mount.
This special release includes a set of Tamiya's Weathering Master powders.