OMG.... $980..... I'll stick to the sodium acetate heating pads for $10 thanks.
R..
My instructor researched a bit & built his own using a heated motorcycle vest, a dry plug-in port, a little wiring, wiring adapters & a LiON battery canister (the most expensive part) with the appropriate end plugs, for about $450- $500. He has the plug port set where it lays under the waist fold of his drysuit & the cord is also routed under the waist fold. It took a little creativity, but actually works quite well, when he has to dive to the bottom of our quarry (42* year round below 60 ft).