Eye bolts and studs are all stainless steel for long life. 
SPECIAL ORDER SABRE 2:1 CUBE Balun™ – (1.8-30 MHz)
(Original product part # was 770013S - circa 1999)
Model SABRE-2-2000 is a 2:1 (100:50) quad core balun used to translate a 50 ohm input to 100 ohms at RF power levels up to 2000 watts PEP when used with a matched load. This assembled balun features a quad core configuration for increased power handling and flatter frequency response to 31 MHz. With a matched 100 ohm load the SWR over the frequency range 1.8 to 30 MHz is shown in the following table measured with an AIM 4170 network analyzer. Notice that the conversion from 100 to 50 ohms is very consistent from 1.8-31 Mhz and SWR is less than 1.5:1 over the range allowing easy tuning by most radio internal antenna tuners or an external tuner. Graph is for a 2:1 balun often used with delta loop, log periodic, horizontal loop antennas and HF Radar.
Input connector is 50 ohm type N (SO-239 also available - inquire).SABRE-2-2000 is in a NEMA 4x4x2 weatherproof box with mounting flanges at bottom to attach to fixed location (mast, wall, beam antenna, etc.).
Iron powder cores are more stable than ferrites and do not saturate as easily so they are best for tuned circuits, filters, and high power inductors. They come in different “Mixes” for use at different frequencies. For best “Q” use the Mix specified for your frequency.To find the number of turns to give the desired inductance for your coil use the formula below:
Turns = 100 x 
Toroid Dimensions
To order specify core size and mix (e.g. T200A-2). Available in sizes that have µH per 100 turns shown in table.
All iron powder cores are special orders. Please allow one week for shipment after order received.
The iron powder cores shown in the above tables are primarily used for either high power feed line chokes for common mode current reduction or for 4:1 and 9;1 very high power transmission line transformers.
For high power feed line chokes, choose the inside diameter of the iron powder core closest to the transmission line outside diameter and use 6-20 cores at the junction with the antenna feed.
For 4:1 (50/200 or 75/300 ohm) transmission line transformers in the range of 1.8-30 Mhz, select the size appropriate for the power level as follows:
T200A x 2 = 1.5KW
T300A x 2 = 2.5KW
T400A x 2 = 5KW
Use Mix 2 for all the above transmission line transformers. Fully assembled and enclosed units are available for each of the power levels. Click HERE for information.
4:1 transmission line transformers using iron powder cores are typically used for ladder line to 50 ohm coax connections
For .1 – 2 Mhz wide band transformers use Mix 26 which has a higher permeability and requires less turns to achieve a given inductance. Mix 2 has almost constant permeability from 1-30 Mhz. Mix 26 has an initial permeability of 75 at .1 Mhz and gradually decreases to about 10 at 30 Mhz. For high power AM broadcast range (.5-1.7 Mhz) transformer, use Mix 26 to reduce the turn count.
Minimum order for iron powder cores is $50
Shipping on larger cores in quantity may be more than $10 – email/call for quote.