Large, 25.7-cu ft -86°C ultralow temperature freezer is designed to preserve the most sensitive, high-value biologicals and is suited for repositories and medical research facilities. The unit accommodates up to 576 2-in boxes. Ultra-low temperatures are maintained with two completely independent cooling systems. The system stores biological samples securely by serving as a fail-safe mechanism, with two independent refrigeration circuits that include a closed-loop, cold-wall evaporator configured parallel one to the other. In the unlikely event that a compressor fails, the remaining compressor will automatically continue to keep the interior chamber at a minimum of -65°C indefinitely.