These are a 1/2" spacer ring, that not only helps to bring out the speaker in those tighter areas, but these also give you the ability to add a great fun accent color to your system.  These rings were designed to fit with the DS18 6.5" Speakers, but they are a universal fit and will fit with many other speakers.

These speaker rings are sealed for marine use if installed correctly.  These fit between the Speaker and the mounting area.  These rings are availiable in 6.5", 8", 10", and 12" sizes and there is a listing for each size and quantity.  This listing is for a 4-Pack of these 6.5" speaker rings. 

You are able to use a single color, or you are able to install a RGB Remote or WIFI transmitter to these spacers, and have the ability to change the color to what you want or change the colors up.