Box type cocnealed stainless steel flush bolt are usually used in fire doors, hotels, apartments, room doors, etc. Among heaven and earth bolts, stainless steel 304 bolts are the most high-quality, because stainless steel 304 heaven and earth bolts are resistant to high temperatures and can be used on fire doors. It is corrosion-resistant and durable, reducing the replacement cycle. The RDA-24 stainless steel fire door bolt from Lelang Hardware meets the above conditions. There are also a variety of sizes to choose from, which is safe and secure to use.