Part of the Signature Collection, these Engineering Notebooks are covered and spiral-bound for durability. Heavyweight paper reduces bleed. The 20-lb paper features a frame front with a 0.5" margin and a 5 x 5 enclosed grid on the back for precise sketches, record-keeping and notes. Each notebook contains an oversized double pocket under the cover for storing loose paper. Perforated, 8.5" x 11" sheets and cover are three-hole punched along the 11" binding edge so it can easily fit inside letter-size, three-ring binders.