The 440-18 is a computer optimized broadband yagi featuring an excellent pattern and good gain across its bandwidth. It can be mounted vertically or horizontally and is ideal for stacking two or more for additional gain. Its light weight yet sturdy construction keep the cost low and the performance high. Use it for ATV, OSCAR, FM, LONG HAUL TROPO, ETC. We guarantee you will be impressed. The heart of the 440-18 is a unique Driven Element Module with superior weather resistance and power handling abilities. All connectors are O-ring sealed to the CNC machined block and internal connections are sealed in a space-age silicone gel with a dielectric strength nearly 4 times greater than air. The Balun coax connectors are triple O-ring sealed. Other key mechanical and electrical parts are CNC machined from 6061-T6 aluminum and all hardware except U-bolts is stainless steel. The 440-18 offers you uncompromising performance, enduring mechanical construction, and long term electrical integrity. Where else but M2.