The HY-Gain TH6-DXX "Thunderbird" is a 6 element beam designed to operate on 10, 15 and 20 meters. It has 4 active elements on 10 meters and 3 active elements on 15 and 20 meters. The "Thunderbird" has optimum spaced elements on a 24 foot boom giving you the best gain while maintaining a high front to back ratio.
The previous model, TH6DX is rated a 5.0 on eHam reviews.
This was used in 2017 at Lowell's Field Day. All plastic parts have been replaced. In excellent condition.