For sale: one used Balun Designs 4:1 unun with a capacity of up to 300 watts. Model 4130svw was designed for use with the S9 vertical, but can be used in many wire antenna applications. The unun has plastic connectors that allow you to use zip cord to mount to an antenna mast.

Item is 5 years old, with 3 years outside on my S9. There is a rusty nut on the radial side, which can be replaced, and the original sticker is missing, but is otherwise in great shape. A look in the interior shows everything is clean, so this unit should work well. However, with all used electronics, no warranty is included or implied.

Great way to pick up a clean unun at a reasonable price! Item is for sale in the U.S. only. Payment expected via PayPal within 2 days of sale closing. Shipment will be via USPS Priority Mail. Happy offerding!

Specs from manufacturer:

Designed for use with wire antennas this unun is small, compact and perfect for quick portable/emergency installations. This 4:1 Unun (200-50 ohms) will easily handle 300 watts and covers 1.5 - 54 MHz. Using this unun will allow transceivers with internal antenna tuners to work most if not all HF bands.  A 28-31  foot wire will allow 40 thru 10 meter coverage and a 43-50 foot wire will provide access to 80 thru 10 meters.  A good ground or counterpoise is also required.

This model also works well with any of the 19, 31 and 43 foot portable verticals and the wing nut model makes setup and breakdown quick and easy.  If you have a 43 foot vertical, a long wire over 200 feet and/or want to run high power, consider the model 4132s or model 4134s which provides additional inductive reactance for enhanced performance on the lower bands.