Pressure grooves books page through convenient, hard cover book Groove along the case-making, and books are back, this book covers and book block do disruption to extend the service life of books.

• 不抬沟槽的册不梢翻阅便当，软皮书壳沿书槽翻动，而册不梢的书背不动，这样书不开背与书芯不离不易分裂，放大册不梢的搁置寿命。