For O2 Sensor.
$21.95
KOSO EGT-02R EVO Dual EGT w/RPM & Water Temp (BA006010-X)
KOSO X-2 Boost Gauge with Wideband Air/Fuel Ratio (BA029001)
KOSO Fast Response Sensor, 40-60mm (28-CKTYPEX)
Koso Air/Fuel Ratio & RPM Data Logger