Three sided older knife sharpening wetstone

Older three sided knife sharpening wetstone one side looks like it might be marble ways about six and a half pounds each stone is 11 and 1/2 in Long and a half inch thick they all do come out if you take the screws off each end of the handles you have to know how to use them if you do get your knife sharper than any other way definitely older I don't know how old because there's no markings or names on it but you can tell just by looking at it outstanding for everyday use. excellent materials and excellent craftsmanship ensure long-lasting durability.