Size: Radiators seem to be a very reasonable size. They fit snugly on my Raspberry Pi 4 and don't add bulk to the board. Thermal: By using heat sinks, my passive temperature was reduced by 4 to a maximum of 10 degrees Celsius without active cooling. I suspect that the increased surface area provided by the heartbeat would greatly increase the efficiency of an active cooling system. Adhesive: Adhesive appears to be quite thermally conductive. It binds strong enough that I'm not worried about the heatsinks falling off in my fixed position use case. I would recommend replacing the adhesive with a more durable one if using this product in an application that may be subject to shock or vibration in daily work. Price: The product looks very cheap for what it has to offer.