Bought for the Rhino 4200 labeller, it is the largest size compatible with that model. Although this size may be too large for many jobs - I tend to use 12mm as a standard for the majority of tasks, although 6mm and 9mm are also often used - having a wider label is sometimes useful. It is for this ability, and the wider choice of substrates, that I chose to add the Rhino to my existing Dymo labeller which is limited to 12mm maximum.
If used to contain a single line of text and the font set to a suitable size, the label will be readable at a moderate distance. It can also accept a second line of text at reduced font sizes.
Although supposedly available in a wide range of base colours, most retailers will not be able to offer more than one or two variants in most sizes and the wider ones may be even more restricted.