We had a cabinet with a light bulb (to generate heat) but we were told that constant monitoring was required (like refrigerator temperature logs). So, we bought a warmer from Cole-Parmer that has a temp gauge.
We have an incubator with a thermometer that we use so that we can monitor temps. According to the PI and other sources we found, it should not be kept at constant temperatures above 86 degrees F because it may compromise the integrity of the product, so we keep the incubator at 85 and monitor.