These are made specifically to fit inside the square and rectangular adhesive labels that are available at Target in the dollar section.
Of course, they can be used otherwise as a label in any other way you'd like.
This resource includes a PDF file with 20 square and 20 rectangular labels that are rainbow themed and labled with common classroom items such as pencils, paper clips, scissors, etc.
It also includes a 30 page Powerpoint that has many different color schemes with a rainbow theme (chevron, diagonal stripes, polka dots) for both the square and rectangular labels. All you simply need to do is add a text box on the labels with whatever you wish! Very, very user friendly!
You may also be interested in a similar resource of mine
Nautical Themed Labels
Beach Themed Editable Labels