Could not be happier for the 60 or so dollars I spent on the Shiva. Great heat retention. Perfect size (not too big or small). Fits perfectly in my D-Nail Iniversal heater standard size. If you buy be careful of durability as the arm is quite skinny and brittle compared to the rest of it. Not a complaint at all for me especially at this price; just something to watch for and take care of. Overall good quality and a superb calue; the best bang for buck that I have personally have experienced and I have tried Greek Glass, Bear quartz, Victory Glassworks, Terporium. They are all fine but cant compare with the heat retention I get from this thing for the same amount of money.