CASS (Collision Avoidance Sonar System), FLS (Forward Looking Sonar), and OAS (Obstacle Avoidance Sonar) are all names which can be used interchangeably when describing a sonar system which looks ahead and is used for navigation. Although there are many products on the market with these names, only FarSounder's products are capable of creating a complete 3D image ahead of the vessel at navigationally significant ranges with a single ping.