These Extra Large Rock grips come in a set of 12. Plastic blow molded Rocks are molded from polyethylene with UV and cold weather protection. These come in 3 different shapes. There are two sets of each 3 different shapes. There are 6 rocks 6 x 4 x 3” and six sets of 6 x 5 x 3”. Holes are 3″ on center.
Please note: There are two holes per rock 3” center to center. One set of two rocks of the 6 x 5 x 3’ requires two different sizes of mounting screws and washers. The one side of the two holes requires a 3/8” x 1 ½” screw or bolt and washer the other side requires one #14 screws or bolts x 1 ½” and washer. The other 10 rocks all require two each #14 screws or bolts by 1 ½” and washers. This product should last 2 years in harsh conditions and up to 5 years in optimal conditions. Some conditions may require replacement sooner