I bought the vest on sale. It takes several minutes to heat up, but the vest starts giving off heat even during that time. The three heat settings are easy to select. However, I still find even the highest setting to be very low and not particularly warm. You really have to wear the vest under other clothes to feel the warmth. I also think the jack plug for the battery in the vest is poorly designed, since it prevents the use of other batteries or power banks. Overall, though, the vest fits me very well in size XL, so I’ll probably keep it.