[What You Get]The set includes 6 pieces Corner Guide and 1pcs 5-in-1 Book Cover Guide,that adapt to different sizes in order to adapt to the different thicknesses of cardboard,the sizes being 1mm,1.5mm,2mm and 3 mm This set of rulers help you in your bookbinding work, from cutting the corners to positioning the cardboard correctly. You can also use it to cover all types of album covers, make spine structures, double covers, etc. [Premuim Material ]The Corn Guides are made of plastic and The Book Cover Guide is made of metal stainless steel,which are not easy to break.suitable to use for a very long time. [How Use the Corner Guides]Place the cut pieces of cardboard in the notches of the corner piece so that they form a corner. Then, place the other corner on the other end of the cardboard and repeat this step with the rest of the corners. Finally, use a cardboard glue to join the cardboard together and you're done! [Wide Application]The guides are perfect for holding corners together while you wait for adhesives to dry.It can be used on book covers, boxes, dioramas, and more. Color: Blue Material: Plastic+Metal Package Contents: 7 PACK Corner Guides Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.