The DX-2 is identical to the DX-1, except for its operating range and calibration.  Whereas the analog meter on the DX-1 ranges up to 10 mR/hr, giving way to an additional audible beep for radioactivity levels beyond that point, the DX-2 goes all the way up to 100 mR/hr or 1,000 µSv/hr with its dual scale meter. The DX-2 still provides the audible clicking as in the DX-1, but lacks the additional audible beep of the DX-1 in exchange for its higher range meter. You can see the difference in the analog meters of the two units below: