Next tutorial from Wyhaq with the AAP-01 GBB Pistol shows how to replace the External Selector... "This video I show how to install replacement upgrade tti selector switch charging handle for the action army aap-01 gas blowback replica. This is a much better selector switch than the stock one, and is significantly easier to use and is an external switch rather than an internal one. These will increase ease of use, fit and finish, and just style overall. As well as providing an additional charging handle."