Late fall on open water, the back end of a cold front, forty minutes of spray on the run out. That is where a vest either works or it doesn't. This one got rebuilt for it. Three heating pads became five, and the two new ones sit in your lower back, where hours on a seat do their damage. One button, three levels, up around 131F on high. SoronaA(R) Aura fill does the rest. Power bank sold separately.