The ultimate test: the morning set in solid-zero temperatures in the car, 200km down, left cup approx quarters full in the car. After another four hours in the chill protection car the rest of coffee was still (hand) warm. In other cups ice has rattled in comparable situations.
Another advantage is that tight. No matter how the cup (with closed valve, of course) is, is, is rolling: Since dripping or strullert nothing out.
Cleaning in the dishwasher goes without complaint, clean the mechanism is simple (unscrew washer screw together).
For what is on offer, the cup is inexpensive.
