Extended slide lock for the glock 43x - Cross Armory Extended Slide Locks

I bought this because it states in the description that it will fit the Glock 43x. When I received it the package says that it doesn't work on that model. I contacted customer support and they reassured me that it does. I tried installing it and it definitely does not fit the 43x. I'm sure it's a good fit for the double stack glock models but will not work in the single stack models (at least not the 43x).