J&M helmet speakers use only the finest internal drivers the industry has to offer. They provide full audio fidelity, a very high power rating and maximum durability, for many years of listening enjoyment. 
The DynaPort porting technology was created to provide the best possible sound in those helmets that have a defined ear pocket shape built into their interior. Some good examples of this ear pocket shape can be found in the Arai or Shoei open face helmets. These helmets have a deep ear pocket cup along with a seam or opening toward the bottom, to allow the porting tube access to the air outside of the ear pocket. *Note - If your helmet does not have this type of defined ear pocket, you will want to choose the Slim-Line non ported speaker 
This configuration allows the sound pressure from the back of the speaker cone to be separated from the sound pressure being emited from the front of the speaker, in the area next to your ear, thus improving bass response and overall fidelity. The acoustic padding on the front of the speaker further separates the two sound pressures and helps direct the sound pressure from the front of the speaker cone to the ear, without the need to press the speaker uncomfortably up against your ear. 
This SINGLE Enhanced-Fidelity 44mm DynaPort speaker includes standard J&M modular component speaker wire plug and a 2" diameter pre-gummed Velcro pad is included, to secure the speaker in your helmet.