Size：1/2" D x 2-1/16" W x 4-3/4"L , thread length: 2-1/2". u bolts 2 inch wide for 2" x 2" square beams and shafts, (please check the measurements carefully before ordering), perfect for boat trailer shop installation, trailer crane, and any boat trailer. Quality：The U-bolts for the boat trailer are crafted from 304 stainless steel, ensuring strength and longevity. Each bolt is capable of supporting up to 100 pounds. These 304 stainless steel bolts are resistant to rust, acid corrosion, and wear, making them ideal for use in rainy and humid seaside environments. Use：First, select the appropriate square U-shaped bolt based on the tube's size. Next, drill holes at the connection points. Finally, secure the nut and flat washer. When installing the nuts, use a hand wrench or socket ratchet. Avoid using an impact driver or high-speed socket driver. Include：4pcs U-bolts + 8pcs stainless steel hexagon nuts with lock ring + 8pcs flat washers + 8pcs lock washers.