U nailed, also known as grass, professional fixed for artificial turf, or construction of fixed. Generally can be divided into: round head U nail, square head nail, U type G grass nail, nail several bent grass. Nail U commonly used specifications: 8ga, 10ga, 12 ga,14ga. One leg length: 4 inches, 5 inches, 5.5 inches and 6 inches, 8 inches. Inside diameter (distance between the two legs): 0.5 inch, 1 inch, 1.5 inch, 2 inch. Surface treatment: light wire, galvanized wire, hot dip, spray, spray paint.