BLACK DIAMOND CHISEL SET ESKILSTUNA SWEDEN BERG?

Rare set of chisels marked BLACK DIAMOND MADE IN SWEDEN in a diamond pattern. Little information on this brand or mark is available. Set of 8 graduated chisels which have had a great deal of effort put into their sharpening. Handles and chisel design are indicative of several Eskilstuna based blade makers, most prominent being E A Berg. Sizes as follows 2", 1 1/2", 1 1/4", 1" , 7/8", 3/4", 5/8", 1/2" (2). Includes newer tool roll in canvas.