A good quality product because Norton didnt design them, Micromesh own the copyright to the filter design. They'll make them again, minimum order of 500, as the filter media is only used on that particular filter. They produce filters for the likes of McLaren. An excellent product and SO much better than the two previous Norton efforts.
Norton were a little odd with etching, I assume it was something offered for free by manufacturers, as they wouldnt have paid for it. The crowns on the V4 pistons were also etched.