The IWI gray plastic parking block is made of 100% recycled PVC (polyvinyl chloride) for flexibility and to resist chipping, rot, and corrosion, has a UV coating to resist wear and for durability, and is suitable for use in parking lots, garages, and other paved asphalt or concrete surfaces. It comes with a U-shaped channel clip for connecting it to another IWI parking block (sold separately) and measures 3-1/2 x 36 x 5-3/4 inches/89 x 914 x 146 mm (H x W x L). (H is height, the vertical distance from lowest to highest point; W is width, the horizontal distance from left to right; L is length, the horizontal distance from front to back.) This parking block has two holes with 11/16"/17mm diameters for use with two 12" spikes (sold separately) for installation on asphalt surfaces, or two 8" lag bolts with concrete anchors (sold separately) for installation on concrete surfaces. Installation instructions are included. Tools for installation are sold separately.IWI manufactures loading dock and material handling accessories for the warehousing, freight and shipping, and manufacturing industries, among others. The company, founded in 2004, is headquartered in Sparks, NV.What's in the Box?