400 strands times 0.04 = 16. So i got 3 orders expecting this stuff to be 16mm thick. Turns out complete wite is about 1.2mm - so i got the 3 orders on the one roll but they kept the extra shipping charges! I checked the wire but trying to count the individual strands is like moving shopping trollies with a bus - the wires are very fine and 400 looks right. It was the correct length. So no need to bother checking. Some instructions on how to handle it would be nice. Because their so fine its like handling the cables of the brooklin bridge & yr the monster trying to be dellecate {when unwinding and having it twist etc..}. Look forward to my experiments. Thankyou. But next time credit back the shipping.