The heads for timpani Evans Strata are already in the better and more important symphonic orchestras from around the world. They are designed and made with a pre-tension moderate to ensure that head perfectly settles in the bowl and so get a perfect tuning. Made with a layer of 7.5 mil which provides a clear sustain and easy and accurate tuning. All heads Strata Timpani are pretensed with a black powder-coated inner ring that provides greater tuning and stability to the head. 

If what you're looking for is a classic natural skin sound but you don't want to give up the tuning comfort of a head synthetic, this is your head.

About Evans Drumheads
This American brand has been doing heads since 1956 and is possibly the that more innovations has done in recent years the manufacture heads. Their constant advances have much to do with how we hear the drums today both in recordings and in directs.
Today an important part of drummers and percussionists from around the world and all styles have Evans as a travel companion in their careers.
Put the list of artists using Evans would be endless but we could put Jojo Mayer as an example.