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.