Baby incubators are medical devices that maintain a stable, constant temperature for premature or ill infants who are unable to regulate their own body temperatures. They are used to sustain warming for babies weighing less than 1500g or those with conditions like sepsis or severe breathing disorders that prevent kangaroo mothercare. Proper use requires cleaning the incubator daily with disinfectant, emptying the water reservoir weekly to prevent bacterial growth, and setting the temperature according to the baby's age and weight.