The shirt has sensory receivers and fibers that are woven into the fabric to give readings that track a range of stats like heart rate, breathing, movement intensity, energy output and stress, as well as steps taken and calories burned. It’s super breathable and really comfortable to wear. You can throw it in the washing machine after removing the black box and it’s ability to track your breathing is really neat. But at $300 the PoloTech smart shirt just seems like a luxury workout accessory.