I have tested a escort ZR3 against my Ultrlyte LTI 20-20. It seems that the Ultralyte and the Laser Atlanta S is the hardest guns to jam for the LED jammers. Of course every LED jammer is different. My Blinder spanked a stalker LZ1 just a week ago. Stalkers are much easier to jam than the Ultralyte's. The beam on the Ultrlyte is much tighter and narrow. Plus you have to be a real good shooter with the Ultralytes versus the stalker. A steady hand on a Ultralyte is pretty dangerous.