*To install the glass breaker on your Gen 1 MCK, you need to remove the flashlight plug/flashlight/laser. On Gen2 MCKs, there is no need to do this

*On MCKSIG models, the glass breaker works with a flashlight/plug installed. 
*On M&P MCKs, the flashlight must be removed before installing a glass breaker. The flashlight plug does not need to be removed. 
On the MCK21, the flashlight and/or plug needs to be removed prior to installing the glass breaker. 
*Fits Micro Roni 3rd Generation