The Whistlestop is a telephone adapter for hearing aid users designed to eliminate the whistle-squeal feedback that occurs with hearing aids. The adapter snaps onto the telephone to hold the hearing aid away from the telephone. The Whistlestop is constructed of durable plastic, and is designed to work well with most styles of hearing instruments. Clean with soap and water-- the adapter uses no batteries and has no moving parts. Works especially well with in-the-ear hearing aids, but will work well with all styles. Choice of round or square adapters (can also request one of each). Device requires a hearing aid, but a "T" switch or telephone amplifier is not necessary as you use the volume control on your hearing aid. Fits in purse or pocket for use anywhere.