M5Stack FIRE Kit, as one of the M5Stack iot development kit series, is an upgrade from the Gray kits. Providing 9-Axis IMU sensor(6-Axis posture acceleration measurement + 3-Axis magnetic measurement), it equips with more hardware resources : 16M Flash + 8M PSRAM , enhanced Base (M5GO Base and M5GO CHG Base), larger battery, etc. For those developers who ask for hardware performance, Fire will be a good choice.