Material: The product is made of rubber and brass, which is durable. Easy to install: just put the fastener in the hole, insert it and fix it. tighten to enlarge the sleeve. Size: 12 x 14mm (W x H), Thread Size: M6. Application: Usually used in car racking systems, kayaks, motorcycle windshields, multifunctional truck equipment, compressors and motors. Package includes: 10 x lock nuts.