FishEng&';s Rod Holder Extensions with heavy duty 3/8 billet aluminum guaranty your rod holder will remain security attached to your boat, always keeping your rod within reach. Available in powder coated & plain finishes Machined from 3/8" Billet Aluminum Aluminum base and tension knob Heavy duty construction Dimensions w/Base: 8 in.: 10" x 4" x 3" (L x W x H) 15 in.: 17" x 4" x 3" (L x W x H)