The RS-1i is the Masterpiece of the Grado collection, the Top-Of-The-Range product which oozes class both in looks and sound. Featuring handcrafted Mahogany earpieces made using an intricate curing process, Grado has been able to optimize the tonal quality. The RS1 uses dynamic transducers in an open-air configuration, the cups being open-backed. The result is a smooth, coherent sound with detailed dynamics. Frequency response ranges from 12-30 kHz and the drivers are matched to 0.05dB. Weighing 9 ounces, the headphones are an example of the wonder of mother nature with a gorgeous, honey-colored look.