The Sentina is a single unit that provides 180 degrees of blind spot coverage, and has the ability to add up to 3 Braze Echo Heads, each providing 45 degrees of coverage (sold separately).
The Hydra is a black box, which includes 3 Braze Echo Heads that can be placed anywhere on the wheelchair and each provide 45 degrees of coverage. The Hydra Plus unit can accommodate up to 8 Echo Heads.
To compare these products, click here! The Sentina plus is our most popular unit, due the robust coverage and flexibility of coverage, but to determine which system is best for you, try our product selection flowchart!