The Protech by Hirsch SDI-77XL-HS-H20 PIRAMID is a high-security, dual-technology outdoor motion sensor with built-in anti-masking protection, engineered for demanding perimeter applications requiring a balanced medium-beam detection pattern. Featuring Lens H20, this sensor delivers a targeted 100 ft. x 20 ft. (30 m x 6 m) detection zone — ideal for walkways, building approaches, loading docks, and perimeter segments where a deeper reach with moderate width provides optimal coverage. The HS (High Security) designation adds anti-masking components that detect any attempt to block the passive infrared or microwave sensors, locking the unit into a constant alarm until the obstruction is removed. Combining PROTECH's proprietary Stereo Doppler microwave technology with a dual-element passive infrared sensor in an "And Gated" configuration, the SDI-77XL-HS-H20 reliably identifies slow-moving, fast-moving, and crawling intruders while maintaining an exceptionally low nuisance alarm rate. Ten-position digital range and sensitivity controls allow precise field tuning, while balanced temperature compensation automatically adjusts both technologies to maintain performance from -40°F to 158°F (-40°C to 70°C). Housed in a rugged metal enclosure with a protective weather shroud, the sensor features a user-selectable solid-state Form C relay output, tamper switch, and swivel mounting with 180° horizontal and 90° vertical adjustment. Operating on 10.5 to 28 VDC, the SDI-77XL-HS-H20 is the trusted choice for high-security perimeters demanding false-alarm-free, anti-masking-protected, medium-beam intrusion detection.