Here's what A-T has to say...
Audio-Technica's 4000 Series Wireless Systems provide outstanding clarity and versatility for live performance, regional touring, fixed installations and more. Features include 996 selectable UHF channels per band, IntelliScan™ (which finds and sets the best available frequencies on linked receivers) and True Diversity operation reduces dropouts. The 3000 Series is specially designed for wireless users ready to step up to an advanced system. Features include 996–1001 selectable UHF channels per band, nine pre-coordinated frequency scan groups simplify multi-channel wireless system setup, and True Diversity operation. The 2000 Series provides easy setup, clear sound and automatic scanning. All 10 channels are compatible, with no confusing frequency groups. Other features include True Diversity operation and automatic frequency scanning.
Pricing and Availability:
The rebate details can be found online at audio-technica.com. Claims must be received by January 31, 2011, to be valid. Along with the mail-in rebate form, buyers must simply attach the original sales receipts for the Audio-Technica wireless products with the store name, date of purchase, model number and price paid clearly legible, along with the original UPC code cut from the carton of each product purchased.