COSLUS C20 Cordless Water Flosser vs Waterpik Aquarius Countertop Water Flosser WP-660
What owners say · Updated October 2026
The COSLUS C20 is a cordless model designed for shower convenience, while the Waterpik Aquarius is a stationary countertop flosser built for extended cleaning sessions. Owners highlight clear differences in water capacity, mobility, and pressure settings.
COSLUS
COSLUS C20 Cordless Water Flosser
“An remarkably effective and budget-friendly alternative to name-brand water flossers, though long-term durability can be hit-or-miss.”
Choose it if you want a waterproof cordless flosser with a long-lasting battery for easy shower use.
Waterpik
Waterpik Aquarius Countertop Water Flosser WP-660
“Unmatched dental cleaning performance that transforms gum health, offset by plastic build quality and long-term leak issues.”
Choose it if you want a high-capacity countertop flosser with 10 pressure settings for cleaning complex dental work.
At a glance
| COSLUS C20 Cordless Water Flosser | Waterpik Aquarius Countertop Water Flosser WP-660 | |
|---|---|---|
| Ease of use and design complaints | 18% of reports | 0% of reports |
Share of each model's owner reports raising ease of use and design; the category average is 16%.
Where owners report a difference
| COSLUS C20 Cordless Water Flosser | Waterpik Aquarius Countertop Water Flosser WP-660 | |
|---|---|---|
| Placement and shower compatibility | Owners value the waterproof design that allows for easy use directly in the shower. | Owners note that the unit takes up counter space and is not suited for travel or shower use. |
| Pressure customization | Owners appreciate adjustable pressure modes that suit sensitive gums and dental work. | Owners appreciate 10 levels of pressure customization with controls conveniently located on the handle. |
| Long-term failure points | Owners report occasional motor failures after several months of use. | Owners report persistent leaks from the handle, hose, and reservoir base, along with brittle plastic components. |