This is one the handiest apps on my iPhone. Really a set of five apps, so the $2.00 price is a bargain. If you ever need to hang a picture or level a pool table, this is the app for you. Also a fun way to show off the motion sensor on the phone. I wish the ruler moved, but there must be some technical hurtle, because the other ruler programs that do move all state "accurate witin one inch." That's not really acceptable for most projects, so I can see why the creator chose to make it fixed.