heated vest, lightweight heating jacket usb electric body warmer clothes for men and women(l) rrtizan <b>rrtizan heated vest keeps you warm and cozy in chilly days. </b><br><br> <b>how to use</b><br> 1.connect your 5v power bank with the vest (usb plug inside your left side pocket). <br> 2.press and hold the button(upper left chest) for 3 seconds to turn on the heating system. <br> 3.power button will blink on and off which means heating system in pre-heat mode. <br> 4.tap the button to adjust the temperature-- high level (red)/ medium level (white)/ and low level (blue). <br> 5.press and hold for 3 seconds to turn off the heating system. <br><b>notes</b><br> please do not use more than 5v input dc power to avoid safety issues. <br> prohibit the use of products while sleeping. <br> not for pregnant women, young children and those who can not express their willingness. <br> not use for people with pacemakers. <br><br>