Unibind SteelBack, 18MM, 130-160P, Aluminum, 50/BoxThe Unibind SteelBack Spines are compatible with your own front and back covers or Unibind cover sets. Original in design, the spines do not require crimping. SteelBack spines are also compatible with all Unibind systems. They are ideal for customized documents and perfect for fast-turnaround projects. Bind up to 160 pages with this 11" spine that allows you to make portrait letter-size documents or landscape 11x17 documents. This specific item has been discontinued, so supplies are limited. The item has been replaced by the UniCover Spine.