Installing an ALG AKT trigger in a KP-9 is rarely a "drop-in" experience without minor fitting.
Are you planning to install one yourself, or are you an existing setup? alg-trigger-kp9
You often need to squeeze the trigger while rotating the safety lever back into position during the initial install. Installing an ALG AKT trigger in a KP-9
The most famous part of the story. Most KP-9 users must install the included roll pin into the trigger tail and file it down until the safety can just barely engage. alg-trigger-kp9