The Germans developed 2 types of extended width tracks for Panzer II/IV based vehicles.  One style popularly called "winterketten" which was essentially a long flat extension which reduced ground pressure and used a standard length track pin.  This type has been offered in plastic, white metal workable style and resin link and length so no problem there.  The other style which almost resembles a Tiger I track and uses a longer track pin is referred to as "Ostketten".  These two track types have caused a bit of confusion and people sometimes use both names to describe the "winterketten" as found in the DML kits.

Cromwell Models is the only manufacturer I know of that produces the Ostketten tracks as found on StuG III, StuG IV and Hummels.  Photos showing these tracks are reasonably hard to find, but the excellent Armageddon book on StuGs has almost a dozen shots of them mounted on StuG IIIs and IVs.  Cromwell's track set features resin cast sections in short and long lengths.  Casting quality is good with no airbubbles or warpage on my example.  Detail is good, but not quite up to Modelkasten level.  However, that being said, they are the only option on the market right now and should look very nice mounted on your favorite StuG IV… right Mr. Leeman?

Cromwell Models Website