"units" used to be a nice litte free utility, but "version 2.0" became useless junk. Nasty Ad always shown on bottom, unnecessary features (who converts electric inductance or air dencity in daily life?) and hopelessly unstable. Just to switch units (not even typing a single digit!) several times makes it crash on my iPhone3. Yes, iPhone3 is pretty old, damn slow and memory-restricted platform. So I had two choices; upgrade to iPhone4 to continue to use units 2.0 or uninstall it. I just uninstalled. Farewell units, you were a good application but not anymore.