The TR-4 S16 is a limited edition Pro-Tech automatic, serial numbered 12 out of a run of 20. This Custom TR-4 model features a 4" Smoky Gray DLC finished CPM-D2 steel blade with a plain edge. The ergonomic handle is stonewashed stainless steel with a grippy knurled texture. The TR-4 is a knife that will not let you down. It fires hard, locks up like a rock and feels great. The TR-4 has a pocket clip (tip up) on the back of the knife for easy carry.