High quality. 316L stainless steel + industrial grade UPVC guide rods. Metal brackets and guide rods are absolutely sturdy and will not bend easily if your boat hits it. Top quality, will not rust after long exposure can easily face seawater. All mounting components are made of 316. Guide your boat with ease. Our PVC white guide bar provides you with clear visual assistance and makes it easier to guide your boat into and out of the trailer. Also, know the proper launching depth for safe loading and unloading to prevent the boat from falling Two PVC pipes with end caps are securely attached to the brackets, and they prevent the boat from being scratched. It takes no effort to install and protect your boat. Adjustable width: The width of these trailer guide bars can be easily adjusted, extending up to 13 inches. They are compatible with trailer frames less than 3 inches wide, 4-1/4 inches high, or 5-1/4 inches high. The white PVC column has an OD of 2.48 inches and a thickness of 0.2 inches. The metal support is a 1-1/2 inch square square tube Note:Overheating of 316 material U-bolts and nuts can cause a locked state.So, if you want to avoid the nut locking onto the U-bolt mentioned in the comment, please apply lubricating oil to U-bolts before installation. For any buyer who did not notice this issue and failed to install the bracket, we can provide free bolt replacement service. Boat Trailer Guide-ons-60", 2*316L stainless steel Trailer Post Guide on, 2*UPVC tube trailer guide bars, mounting hardware included , for boats, kayaks, canoes, fishing boats, ski boats and more