Before the PCH17, if you wanted a Charging handle and an optic site, you had to choose between one or the other, or modify your weapon by cutting your slide. With the PCH17, you can have both with no modifications to your weapon. The unit installs in minutes and once your done, just mount your pic rail optic. Thats it. Compatible with Glock 17/19/22/23/24/31/32/34/35/45 and G17T/G19T