The tough, rugged Mil-Tac TDP-1 Tactical Defense Pen ($90) is appointed with virtually indestrucitble, aircraft grade ,anodized aluminum business end, cap and integrated clip. This effective defense tool measures 5.25-inch in length with less than a half inch in diameter and weighs a little over an ounce. The TDP-1 also comes standard with a refillable cartridge and offers a smooth writing performance that also kicks ass.