Two center-folded endpapers are glued together with a DUROTEX spine strip, leaving a gap between the endpapers that roughly corresponds to the thickness of the book block. You can insert dual-endsheets in the feeder of various perfect binding machines instead of the softcover envelopes. This means that high-quality, mountable hardcover book blocks can be produced even on simple softcover perfect binding machines. Dual resolutions are our absolute specialty; we manufacture individually to customer order according to your wishes, high quality, quickly and inexpensively.