Review on High-Quality White Plastic Flush Type Plugs for Industrial Hardware Applications by Vincent Blitz

This is just what I needed for a fiberglass shower that required the curtain rod to be raised. Fits very snugly into 1/4" drilled holes. None of this will fall out. As mentioned, the center portion of the connector is somewhat see-through after installation, so a small bead of white caulk before installation will solve this problem. I didn't find it reprehensible so I didn't. Very satisfied. Highly recommended.