Stapler binding Exercise books 1.size:A4, A5, 160*220mm, OEM, etc. 2.Cover materials:white card, Art paper, Kraft paper, etc. 3.inner:20s, 30s, 40s, 50s, 74sheets.4. Inner paper:57g, 60g, 70g, 75g offset paper5.usage:school/ office/ daily use6. Binding: Stapler/saddle stitch/ perfect binding....