4.5" Bloc Loc Half Square Triangle square up ruler
The PERFECT ruler for squaring up the 4.5" or smaller half square triangle. This ruler has a channel through the center of it that the half square triangle seam sits in, locking the ruler in place and eliminating that "ruler rock". A must have for all quilters! Our FAVORITE square up rulers!!
Watch how they work - http://www.blocloc.com/blocloc.htm