Product details
Cordless, USB-Powered and Rechargeable Are Different Labels
A reference to USB tells you something about a power connection, but may not fully explain how the product operates. Look for an explicit rechargeable description and operating instructions.
Ask what the cable does
Is it used to charge an internal battery, required during operation or supplied for another component? A photo of a cable does not settle the question. Neither does a retailer using “USB power” as shorthand.
Read cordless separately
Cordless describes operation without an attached power lead; it does not by itself identify the type of battery. Dear Tingle's Drift description expressly says cordless. Dot's description expressly lists USB charging. Those are precise claims to read as written, not permission to add unlisted battery specifications.
Do not assume operation while charging
A rechargeable device may have restrictions on use while connected. Follow the manual rather than treating a charging cable as an optional operating lead. Never infer water-use permission from a cordless label.
Make the buying question unambiguous
Ask: “Does this exact version operate from a rechargeable internal battery, and must it be disconnected from charging before use?” Also confirm the included cable and any separate adapter requirement.
Dear Tingle's connector comparison explains the physical charging arrangements once that question is answered. Clear power terminology prevents a practical mismatch without relying on the age, price or appearance of a product.