This document introduces the features and characteristics of AD8229-KGD, an ultralow noise instrumentation amplifier designed for measuring small signals in the presence of large common-mode signals. The device features 1 nV/√Hz input noise, 45 nV/√Hz output noise, 126 dB CMRR, and 15 MHz bandwidth. It is suitable for various harsh environment data acquisition, exhaust gas measurement and other occasions.