Check the listing for details. Regal RD-40 Resonator Vintage Sunburst Square Neck. Condition: New. Listed at 615.00 USD. At the top of the line of the Regal Studio Series Resophonic Guitars, the RD-40 Resonator has been redesigned from the inside out making it one of the best values when it comes to truly vintage-inspired, professional featured, resophonic instruments. Using Regal's many years of experience in the development and construction of traditional American acoustic instruments, they discovered ways to improve upon the most legendary designs from the past without pricing them out of the reach of any level player. Only the finest materials are used to create these new designs that reminisce of the past, while still meeting the demands of today's modern players. The new body shape takes its cues from instruments of the past; while the real secret to the tone of these instruments lies within.