Barrett Vortex Impact 4000 Ballistic Rail Mounted Laser Rangefinder, Tan, Equipped With The Accurate GeoBallistics Solver Backed By A Full, Up-To-Date Bullet Library, On-Board Compass And Exposed Temperature, Pressure, And Humidity Sensors, Manually Enter Speed And Direction With Patented Wind Bearing Capture Mode, Connects Via The GeoBallistics App With Popular Weather Devices Or Local Weather Stations LRF-IMP4000