Image Item No. Description  K9833-1 (Inv)  Rechargeable Battery Set 2 Sets, 2007 Catalog: Sets: MINDSTORMS: NXT  MS1040-1 (Inv)  Accelerometer Sensor for Mindstorms NXT 1 Part, 2007 Catalog: Sets: MINDSTORMS: NXT  MS1042-1 (Inv)  Infrared Seeker for Mindstorms NXT (Version 1) 1 Part, 2007 Catalog: Sets: MINDSTORMS: NXT  MS1044-1 (Inv)  Gyroscopic Sensor for Mindstorms NXT 1 Part, 2007 Catalog: Sets: MINDSTORMS: NXT  MS1046-1 (Inv)  Infrared Link Sensor for Mindstorms NXT 1 Part, 2007 Catalog: Sets: MINDSTORMS: NXT