Put your leash plug where you want it! The EZ Plug heavy-duty is an easy to apply surface mounted leash plug. Application is an instant adhesive (cyanoacrylate) that requires no tools or drilling. EZ Plug attaches to flat fiberglass surfaces. Not recommended for polypropylene surfaces. Recommended for heavy duty (50+ pounds) and hi-temperature (+100 degrees Fahrenheit). The twin kit includes two (2) EZ plugs.