World Wide Stereo via eBay offers the Klipsch Reference S4 Premium In-Ear Noise-Isolating Headphones, model no. 1013730, for $39.99 with free shipping. That's $2 under our mention from five days ago and also the lowest total price we could find now by $2. Features include four different-sized ear tips, storage case, 10Hz to 19kHz frequency response, and more.