S-hoops are a type of hoops (also called rims) for drums.
The S-Hoop, or Safehoop, was designed by the late Rick Barrickman in 2004. Shortly after launching the design, he was awarded a patent for the hoop and The Safehoop Company was official.
The "chamber" that's created between the beveled edge and the drum head gives a drum a significantly different sound. The beveled edge also protects a drum's bearing edge.