A charity auction featuring Keith Urban's vintage Airline electric guitar will conclude Wednesday (Nov. 24). Proceeds will benefit flood relief efforts in Nashville, as well as fire and rescue departments in the area. As of Tuesday morning, bids had reached $2,100. The Nash2O auction website indicates the guitar is a classic early '60s model made by National and that Urban "loved the throaty growl of this guitar when it was cranked up." Other instruments currently up for bid include Duane Eddy's signature model Gibson electric, Vince Gill's prototype of a signature model Fender Telecaster, Amy Grant's McPherson acoustic and Kathy Mattea's Taylor K15 Acoustic. The fourth installment of the ongoing auction, featuring guitars from Peter Frampton and Brad Paisley, will begin on Nov. 29. All instruments were damaged in the Nashville flood in May and donated to raise money for continuing flood relief efforts.