The D1B05 is a single-pole normally-closed (SPST-NC) reed relay manufactured by HASCO Components with a 5 VDC nominal coil voltage and 500 O coil resistance. It features a must-operate voltage of 3.75 VDC and must-release voltage of 1.0 VDC, with a rated coil current of 10 mA and maximum continuous voltage of 7 VDC. The relay exhibits fast switching characteristics including a 0.5 msec maximum operate time, 0.5 msec maximum bounce time, and 0.2 msec maximum release time, with rhodium contact material providing 100 mO maximum initial contact resistance. It is rated for 10 VA maximum power, 200 VDC maximum switching voltage, 0.5 A maximum switching current, and 1.0 A maximum carry current, with a breakdown voltage of 250 VDC across open contacts and 500 VDC between coil and contact. The D1B05 operates across -40°C to +85°C and is suitable for signal-level applications requiring reliable low-power switching in industrial control, telecommunications, and instrumentation systems.