Uxcell M6x50mm Expansion Bolt 304 Stainless Steel Polishing 10 Pack Description: 1. Material: Made of 304 stainless steel anti-oxidation anti-rust anti-corrosion durable. 2. Application: Suitable for concrete and dense natural stone metal structure metal profile support plate bracket railing wall etc. Not for block or brick base material. 3. Features: The thread is longer and easier to install and is usually used in heavy facilities. 4. Usage: Made a hole into the base material remove debris from the hole use a hammer to drive the bolt into the hole and then tighten the washer and nut by using a wrench.