Easy-tune "bare-hands tunable tip", High power handling. DETAIL: All "FS" antennas are compatible with autos, trucks, vans, motorcycles and ATV"s in a single antenna configuration when metallic ground plane is available. Or, they may be used in dual (co-phased) configuration on any vehicle made from any type of material. Like all CB antennas, the "FS" antennas should be fine-tuned (SWR) in their final mounting location. If you have ever tuned a non-tunable tip antenna, you will have a real appreciation for the "FS" antennas. To tune a "FS" antenna, you just pop-of the tip and turn the adjustment screw up or down as needed. All "FS" antennas exceed the requirements of any CB radio, new or old. Aside from the hi-performance loading coil that maximizes the transmit/receive functions of your CB, these top-loaded antennas will also receive the NOAA emergency weather alert and national weather broadcasts for radios with those features. The "FS" antennas are 100% American made with 100% American materials. To maintain a balance between flexibility and ruggedness, we use a custom blended, glass fiber reinforced shaft. Each is wound with heavy insulated copper wire to prevent the oxidation and shorted windings often found on non-Firestik antennas. The tunable tip mechanism is made from rust-proof brass and has a rubber o-ring to hold the adjuster in place after tuning. Our 3/8"-24 threaded base has a tapered contact point that works especially well with Firestik mounts and accessories. The tapered "lug-nut" effect transfers stress away from the threads and reduces the possibility of vibration induced loosening of the antenna in its mount. Each antenna is covered with a static reducing, water-tight sleeve containing UV and pigment stabilizers. For peek performance we recommend that you use one of our 18-foot Fire-Flex coaxial cables with these antennas. All "FS" series antennas are factory bench tested for resonant frequency and overall quality.