The Holland Green Science Magma Cart fillers feature a patented heating rod design for easier and more accurate dispensing. In as little as 3 minutes, heat up your product to a set temperature and maintain a constant temperature effectively. There are 2 models the Magma 25 and the Magma 50. The Magma 25 volume can be increased with steps of 0.5ml starting from 0.5ml up to 2.5ml. And the Magma 50 volume can be increased with steps of 1 ml starting from 1 ml up to 5 ml.