I bought the 300mm version of this product and I like it the most. The materials feel comfortable, the engraving is clear. My problem is that 3/4 of the holes were made too small to be able to use 0.5mm thick lead for marking. The oval holes work and allow you to mark at half a millimeter intervals which is accurate enough for me but frustrating and takes getting used to just using these holes. The top and bottom rows of holes 1mm apart and the center top rows of holes 0.25mm apart are too narrow to be used with the wire provided/advertised.