The undergravel heating cables JBL ProTemp b40 and b60 now come equipped with a 24 volt transformer. The 24 volt version is more reliable than a 12 volt version, as long-term tests have shown. Undergravel heating cables are very popular with aquarium enthusiasts with densely planted aquariums, because they create a better water flow at the bottom of the aquarium and thus wash more nutrients to the plant roots. This in turn leads to a much stronger and healthier plant growth. A control unit is not necessary with JBL’s undergravel heating cables because their capacity is always adjusted to fit perfectly with the aquarium size, without the need for complex and expensive steering technology.