Features: The kit adopt the the large size NXO-100 magnetic, 1-30MHz shortwave, can withstand high power 100W-200W. It is an perfect kit for making 1:1, 4:1, 9:1 and other magnetic ring baluns. It is DIY KITS not a finished product. Kit soldering requires a certain foundation of electronic technology. Circular models: NXO-100, Circular material: nickel zinc ferrite Magnetic conductivity: 100, Overall dimensions: outer diameter 31 mm x height 7 mm x diameter 18 mm Center frequency: 15 MHZ, Application frequency: 1-30 MHZ Waterproof Case Size: 65mm x 60mm x 35mm NOTICE: This item's shell no punch holes. Because there are three types of antenna position, M seat are the same, different terminal punch locations. need according to their own choice of programs to choose punch antenna location. Types of antennas: 1: 1, 1: 4, 1: 9 three production program antenna optional, 1: 1 and 1: 9 is three enameled hinge, 1: 4 is two enameled wire. 1: 9 balun suitable long-term antenna , with manual or automatic antenna tuner tune-day use. 1: 4 balun applicable LOOP antenna to antenna and Winton (200-400). 1: 1 balun antenna suitable for bipolar DP (inverted V n V), such as antenna (40-100). Kits include 1.5m wire, please fold to 3 fold, each fold 0.5m. 1: 1 winding : three-wire twisted around 7 laps, stranding extent (about 3-4 times per centimeter) 1: 4 Winding : two-wire twisted around 8 laps, stranding extent (about 3-4 times per centimeter) 1: 9 Winding : three-wire twisted around 10 laps, stranding extent (about 3-4 times per centimeter) Note: After stranding, first put heat shrinkable sleeve, and then pass on the ring! Enameled two leaving enough length, a good number of laps around a specified, will be evenly distributed on the magnetic coil, and then start welding enameledwire header and tail. Material: plastic+metal Color: White Package Contents: 1x 1-30Mhz shortwave radio balun kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.