The unique 3-rule construction of the Triple Parallel Rulers allows for greater parallel walk without the diagonal creep associated with traditional designs. The Triple Parallel Rulers are particularly advantageous because they have twice the reach of regular parallel rulers. Additionally, the Triple Parallel Rulers are able to go in any direction (left, right and straight). The Parallel Rulers allow you to go directly to the compass rose with less chance for slippage. These parallel rulers are milled with beveled edges to a 0.19 inch thickness with aluminum arms and handles. The high-quality construction of the parallel rulers has a lifetime guarantee.