This module is designed to heat any perfusion fluid during its passage through a stainless steel tube heat exchanger and intended for use on the microscope stage chambers particularly the MS1 chamber. The heating element is controlled by the very low noise Proportional Temperature Controller, PTC03 or alternatively a regular controller (PTC04) for pharmacology type experiments. This system is able to provide temperature control from ambient to 55 deg. C for perfusion rates ranging from 1ml/min to 6ml/min. The main body is 27mm square and 15mm in height. This compact design makes the MH02 suitable for use with other independent slice and organ baths where space is restricted.