Just a helpful tip. Those of you that occasionally use a bubble level to mount scopes and such should check it for "true" both ways. For instance, if you use the bubble level on a combination square, find a table top or similar flat surface that reads perfectly level. Turn the bubble level 180 degrees and see if the same spot is still showing perfectly level. Chances are it is not. Try this one new levels in the hardware store, too. Many will read differently if turned around. Remember this the next time you mount a scope using a bubble level. Just my 2 pennies worth. Your mileage may vary.