Cold Steel 39FNSZ Double Agent, II, Serrated Edge Blade Designed by custom knife-maker Zach Whitson, Cold Steels Double Agent neck knives are available with either a Karambit or Clip Point blade style. Thin, flat, and super light (a little over 3 ounces including the secure-ex sheath!) they are easy to conceal and very comfortable to wear. Their most notable and eye-catching feature, however, is their double ring handle design Slip your index finger and your pinky finger through the integral steel rings and close your fist for a comfortable and secure grip.