U-nails, also known as sod staples, come in four common types: square head, round head, G head, and capped; materials include cold drawn wire, galvanized wire, galvanized steel wire, and stainless steel wire.

The primary application of grass pins is to secure turf in golf courses, garden lawns, and other outdoor areas requiring grass, such as parks and similar settings. They are also used for fastening lids, mats, round tubes, and more. Operation is simple, and they can be utilized to anchor artificial turf or structures.

Common materials for U-nails include carbon steel, coated with cold galvanizing for appearance, with an average lifespan of around 4 years. However, these steel nails can be expensive, and they work better when paired with plastic ground spikes. These U-nails are used around the perimeter of weed barrier fabric, while plastic ground spikes are used in the middle, ensuring the stability of the weed barrier and solving the issue of the fabric getting caught when the plastic spikes are pulled up.