Today’s crankbaits come in a variety of body shapes and widths, but the lure’s bill is the key feature defining a crankbait as a shallow-, medium- or deep-diving plug.  Crankbaits with square bills are best for running in the shallows from 1 to 4 feet, while a plug with a 1-inch bill will dive to about 10 feet deep.  Crankbaits featuring longer bills have the potential to reach depths down to 30 feet.
 
Time of year is a key in determining which style of crankbait to select.  Although crankbaits will catch some bass year-round, the prime times to throw these diving plugs are spring, summer and fall.