Feature: With stainless steel rings, interior page transparent interlayer design, suitable A4 sized, both positive and negative sides can be used, with 20 sheets can be put in 40 page.Center hollow-out design:Humanized design, use convenience. there is no barrier between the diaphragm in the middle, you can modify the contents of the inside at will.Material: High quality Polypropylene (PP) material (nontoxic and nonradioactive), protective sleeves are water-resistant,durable and stylish.Product Size:32*25*2CM /(12.6 x 9.8 x 0.78 inch),black/white /blue/pinke/(optional)Extensive Use:Change spectrum folder, ideal for kinds of instrument players, musicians.A great assistant for instrument players, musicians, students, office worker, etc.