The 387000866 is a Tunnel Series Direct-to-Air thermoelectric assembly that provides solid-state cooling for small chamber temperature control in analytical and medical diagnostic instruments. The unit delivers 29 W cooling power at ?T=0°C and Ta=35°C (±10% tolerance) using a custom thermoelectric module powered by 12 VDC at 2.6 A nominal current, with an integrated fan operating at 12 VDC and 0.13 A. The assembly features premium fans pushing air across high-density heat sinks to minimize air flow paths, moisture-resistant insulation to prevent condensation penetration into the TEM cavity, and a compact form factor measuring 97.5 × 65 × 86.5 mm with a weight of 0.52 kg. Operating over a temperature range of -10°C to +50°C, this RoHS-compliant unit is ideal for maintaining precise temperature control in laboratory environments where reliable, maintenance-free solid-state operation is required.