The booster plug for this bike, is an easy way to richen up the air/ fuel mixture from just off idle, to 100% throttle.  This provides enough fuel, to work well with our open end cap and opened up air box.  It's easy to install, as it just plugs in between where your "intake air temp" sensor goes, in the the top of the air box.  It puts the A/F ratio around 14.5:1 up until 8000 rpm, where it runs at 13.5:1.  All safe, good zones

Booster plug for 2021-22 KTM 250 Adventure