[Mike U]

I have the Gerbings jacket liner and it works well. I don't use it till it gets below freezing and need to keep it on a low setting or it gets too warm. Not sure if Gerbings has a vest.

Gerbing has Heated Vests I'll list it below.
Like @Hullhorr RIck, I also have Their Jacket Liner and it works as described.
Along with Their Heated Gloves, I stay very warm in the freezing weather.
Mike U.

Gerbing Heated Vest Liner - 12V Motorcycle

Gerbing is the original and most trusted brand of motorcycle heated clothing in the world. This Gerbing Heated Vest Liner is no doubt the best heated vest to keep you warm while riding your motorcycle or ATV. For over 40 years, Gerbing has been trusted to manufacture the highest quality heated...

gerbing.com