DeWalt 33' Laser Square
This laser square is a durable and accurate tool for tiling, with a 33 ft. length and 3 integrated mounting pins for easy placement on walls. It offers IP54 debris/water resistance and an aluminum base for durability, and its two red beams achieve a 90-degree angle for a wide range of uses. Price drops from $93.99 to just $59.99. Shipping is free with Amazon Prime or is otherwise a flat $6 per order.