Then there’s the GE MAC 400, a hand-held electrocardiogram (ECG) device that costs $800 (the cheapest alternative costs more than $2,000), and the Tata Swachh, a $24 water purifier (ten times cheaper than its nearest competitor). The GE MAC 400 uses just four buttons, rather than the usual dozen, and a tiny portable printer, making it small enough to fit into a satchel and even run on batteries; it has reduced the cost of an ECG to just $1 per patient.