Create an even brick or block course with line blocks. Secure the 3-3/8" block on the outside corners of your masonry project with the line knotted to hold it in place. Run the line through the channels on the block to eliminate obstructions and protect the line for wearing down. Retighten the line as you move it up your wall to create a straight row with each new course. Sold in pairs.

Kraft Tool Model No. BL348