Great for the ant farms and we use these they are great.
5 watt model 150 x 140 mm
Do not place heat mat under any Hydration areas with water as the heat will cause the water to evaporate and can flood the nest area.
Place a tea towel or similar over the portion of the mat that is coming in contact with the nest area, these can become quite warm and you do not want to warp the acrylic.
Place the mat as the Ants will move the brood to the most comfortable area that will benefit growth and they may need to move the brood if it gets too hot for the young.