Owfeel Pack of 2 pcs M6 Bolt Ring Shape Screws Stainless Silver Steel Ring shape screw type &lt;br&gt; Made from stainless steel 304 &lt;br&gt; High quality, Anti-rust and more durable &lt;br&gt; Ring inner diameter is approx.16mm/0.63inch &lt;br&gt; Owfeel(R) is our registered trademark,pls don't infringement.