www.heatedwetsuitreviews.com/
For about $200 you can purchase a Quiksilver Cypher heated wet suit vest that's powered by a lithium re-charging battery .... not too shabby for cold water and extending actual time in and on the water?
www.swimoutlet.com has 'em.
Almost as good as a 104-degree hot tub and a cup of hot coffee ..... well, make that just a 102-degree hot tub?
Or, for about $8.50, you can buy a two quart, old fashioned, leak proof, red rubber, hot water "bottle" from ebay .....w/ free shipping .... and put that to work inside your waders or wet suit! This should hit the spot ..... and at $8.50 w/ free shipping ..... is more in my price range .... should be a winner item, as long as it don't leak.
.....the $8.50 hot water bottle inside your wet suit trick ..... how to stretch out the Lake Winnipesaukee, in-the-water, shoulder seasons of April-May-June-Sept-Oct & Nov ..... that's like six extra, get wet, in-the-water, months for the year ...
!
But, does it really work any good???