The centering rule is good and I use it quite often. However, I'm used to squares and Starrett's rules. It's not worth what Starrett makes and it's the highest quality. It is made of stainless steel, has a 24" to 1/16" scale from 1 to 24" on one edge and 12-0-12 on the other edge. The thickness is much less than the fluted "square". " Scale. , flexible. The edges are not very well finished. It looks like it was stamped in a good stamp. The edge is not a cutting edge - you won't cut your fingers unless you're really careful .However, it is not quite finished edge but worth the cost.The quality is good, I use it often.