What's in the box:

KW-trio Disc Binding Ring 25mm Ring Diameter 12-Holes Ruler Fixture Accessories DIY T Mushroom Hole Loose Leaf A4 Notebook Notepad Binder for Travel Office Home School Students (Yellow)

Features:
You can use the ruler to measure the distance or draw a straight line(Has a centimeter and inch marking). It also can be used as a bookmark.
Different ring sizes to suit different thicknesses. 12 Holes ruler fixture is suitable for A4 size paper, 25mm ring diameter can hold 100 sheets paper.
With this binding ruler fixture, the paper can be combined at will, and can be increased or decreased at will, very flexible.
It is very tight and firm in use and will not fall easily. This is a good choice for everyday notebook binding. Notebook can be folded at 360 degrees.
The use of this product may also require a mushroom hole puncher, it can punch paper and then bind the paper with these ring.
The binding rings can be used with TO NOTE notebook, add sheets to your TO NOTE, very convenient to use. Perfect for students, office workers, travelers, designer, etc.

Specifications:
Color: Red/Blue/Yellow(optional)
Type: A5-8 Holes/B5-10 Holes/A4-12 Holes(optional)
Material: ABS,PP
Ring Quantity:
A5-8 Holes: 18 Binding Rings (20mm Ring Diameter)
B5-10 Holes: 22 Binding Rings (20mm Ring Diameter)
A4-12 Holes: 26 Binding Rings (25mm Ring Diameter)
Mushroom Binding Ring Adapts to Thickness:
20mm can hold 80 sheets of paper
25mm can hold 100 sheets of paper (paper is A4 paper thickness)

Package Size:
A5-8 Holes: 25.1 * 9.6 * 2.4cm / 9.9 * 3.8 * 0.9in
B5-10 Holes: 29.7 * 9.6 * 2.4cm / 11.7 * 3.8 * 0.9in
A4-12 Holes: 34.4 * 9.6 * 2.8cm / 13.5 * 3.8 * 1.1in
Package Weight:
A5-8 Holes: 43g / 1.5oz
B5-10 Holes: 52g / 1.8oz
A4-12 Holes: 73g / 2.6oz

Note:
The TO NOTE Notebook and puncher are not included.

Package List:
1 * Mushroom Binding Ring Set