At Cartridgeheater.com, we can make cartridge heaters with diameters up to 50mm and lengths up to 3m so we are never told by customers that they could do with bigger!
we also make cartridge heater as standard to be high watt density design. We will also consider making them as medium or low watt densities. This is sometimes required depending on the temperature required, material and temperature rise. They are a cost effective alternative and we will always consider them where-ever possible