Material Carbon iron and silicon alloy composition with high strength, good toughness, plasticity and machinability. Easy to use Thread pipe cap, just threads the cap to the correct pipe, you can easily to build any shape of frame and shelf for a DIY projects. Application: Wide application for any shelf installation such as bookshelf, table, garden shelf and so on. It is widely used for many DIY projects. Size: 1/2 Inches pipe fitting cap. Guarantee: If there are any quality issues, just contact us and we will refund you