Unable to ship the Echo Triggers to CA, CT, DC, FL, HI, IA, MD, NJ, NY, RI, and WA.   The Echo Trigger allows the shooter to select from 3 different settings: Safe Mode: Firearm will not fire. Semi-Automatic Mode: Firearm fires when the trigger is pulled. Echo Mode: Firearm fires when the trigger is pulled and also when the trigger is released. The Echo AK Trigger is designed to work with stamped AK’s.  As a general rule milled AK’s should also work as long as you are willing to work with the mode selector plate and the trigger blade in some cases.  We have yet to find a gun that it won’t fit in. It’s the parts outside of the receiver that generally causes issues. However, due to the inconsistent nature that many AK-style rifles/pistols have been and continue to be produced,  individual results may vary. Below are some milled AK’s tested to be compatible: Molot-Oruzhie LTD – Vepr Rak Com Bloc Childers Guns- CG1 Century Arms – AK63DS Arsenal – SAM7R Arsenal – SAM7SF Interarms – AKM47 Riley Defense Inc. / Morrissey Inc, – AAM-74 CAI (Century Arms Int) – N-PAP M70 CAI (Century Arms Int) – WASR-10