Kruts , are identical to Zyns. In each there are different styles and weights. Krut were basically the Beverley brand of Zyn. They were also sold with Oympic kits but of course , anyone could specify any cymbal, Krut,Zyn, or Super Zyn, with any Premier made kit, if you wanted to pay for them.
There were two shapes to both Zyn and Krut. It seems like it was a way to use the same weight sheetstock to elicit a lighter or fuller sound. The cone shaped Zyns and Kruts sound more like a China cymbal and when paired can sound pretty tinny and this is where the issue, people have with most Zyns/Kruts, is but in the med. weight and conventional profile both can sound pretty good-----definitely superior to many of the cheaper Paistes and Meinls------and more durable. For all their faults, or perceived faults, they are very good entry level cymbals, they don't crack a lot, bend out of shape and have a reasonably bright , rising shimmer and tight chick. I even know one professional drummer who uses a very light set of Kruts, I sold him, for certain purposes. They are over 50 years old and still going strong.