Operator Series tactical pen has new features their customers requested in the ultimate must-have tool such as allowing the cap to post on the back while writing, an o-ring to help prevent the cap from accidentally loosening and seal out moisture as well as a newly profiled cold-pressed spring steel clip. The new Operator is designed, machined and assembled in the U.S.A. to be the toughest pen on the market, period. These bad boys are made to withstand environmental extremes of heat and cold and function without fail. The new Operator is now even stronger with an increased wall thickness to handle additional punishment. The Operator will withstand nearly 750 PSI without breaking a sweat. A MIL-A-8625 "F" anodizing over a non-marking finish provides a "rock-hard" surface finish to handle the elements and anything else the world throws at it.