Material: The product is made of rubber and brass, which is durable. Easy to install: simply insert the fastener into the hole, insert and tighten to enlarge the sleeve. Size: 12 x 14 mm (W x H), thread size: M5. Application: Commonly used in car shelving system, kayak, motorcycle windshield, multi-functional truck equipment, compressor and engine. Package Includes: 10 x Lock Nuts. Properties: Marine grade rubber with brass threaded insert. Commonly used in automotive trim systems, kayaks, motorcycle windshields, commercial vehicle hardware, compressors and engines. Creates a tight seal and minimizes vibration and shock, vibration isolation helps prevent chatter and tearing. Rubber Well Nuts are a common choice for sealing holes where an accessory is required. Simply insert the fastener into the hole, insert and tighten to expand the sleeve. Specification: Material: rubber + brass Size: 12 x 14 mm (W x H) Thread: M5 Package includes: 10 x Well Nut.