Marshalltown Brick Jointers are recommended for exterior applications to help compact the mortar, ensuring that moisture is unable to penetrate joints for durable construction. Marshalltown Brick Jointers are made from high carbon steel. High carbon steelCreates concave mortar jointsBrick jointers have a convex face for striking concave jointsEach end is a different size for making different size jointsTooled joints are recommended for exterior applications because the jointer compacts the mortar to keep moisture from penetrating the jointConcave joint helps conceal small irregularities in laying and emphasizes the pattern10-1/2" length1/2" and 5/8" joint size