![](https://www.polyscience.com/media/bttj1aju/circulating-baths-texture_0000_textures_119.jpeg?width=576&height=400&rnd=133054074904730000)
The best PolyScience Circulating Bath for your application will depend on a number of factors. Here are some guidelines to help with your selection.
You will need a Refrigerated/Heated Circulator if your working temperature will ever be near or below ambient. Applications that require maximum temperatures above 160°C or ±0.01°C temperature stability require Circulators with Performance or Advanced Series Temperature Controllers.
A Circulator with a small reservoir is generally suitable if you require external circulation only and the heating/cooling demand is moderate. If the external heating/cooling demand is high or you will be putting samples in the internal reservoir, a Circulator with a larger reservoir will be required.
All PolyScience Temperature Controllers can be used for close-loop external circulation. If open-loop external circulation is required, or if your application requires a flow rate above 3 gpm (11 l/min), a Circulator with a Performance or Advanced Series Controller is required.
![](https://www.polyscience.com/media/q2mlxvyk/sd15h_wide_011-large.jpeg?rmode=max&width=1200&height=0&rnd=133059286806330000)
![](https://www.polyscience.com/media/djtplx3q/cooling_charts-largest.png?rmode=max&width=1200&height=0&rnd=133059293980800000)