Cominolli safety for Glock

My wife loves Glocks and is absolutely deadly with them but wishes they had an external safety for carry in her purse and bags.

I recently found the Cominolli (http://www.cominolli.com/) saftey that can be installed on any Glock.

Any experience with them? And please refrain from superflous opinions about whether a Glock needs an extrenal saftey or not - I want to know who's used the Cominolli safety and what those who have USED them think of them .