This is the Altitrak Flying Model Rocket Altitude Finder from Estes.

FEATURES: How high did it really go?  Next time measure it with this easy
            to use device!
          Follow the rocket in the sights to apogee and release the trigger to
            lock the reading,
          Easy to read display gives altitude in meters along with the
            elevation angle.
          Great for school and science projects!
          Includes detailed instructions and full one year warranty.

INCLUDES: One Altitrak Flying Model Rocket Altitude Finder.

REQUIRES: Assembly
          White Glue
          Adult Supervision

COMMENTS: Keep away from children under 3 years of age due to choking hazard.