Here is a "Carboy Heater" from Adventures in Homebrewing.
Here is an "Electric Fermentation Heater" from Northern Brewer.
I just learned yesterday that "Fermwrap" is a product from MoreBeer. Looking at the pictures, the Fermwrap looks identical to the non branded products, but I've been able to find the non branded products cheaper than the Fermwrap.
I went ahead and bought more Fermwraps just to be consistent with my previous purchases.
However, are they perfect substitutes for each other, or is one superior? Has anyone tried both?