Silicone Horn Stand Amplifier Speaker for iPhone 4G Black Silicone Horn Stand Amplifier Speaker for iPhone 4G BLKSlip the horn speaker onto your iPhone for low-fi amplification simplicity. Using old-fashioned acoustical science, the Stand adds 13 decibels to the sound (without asking for an erg of battery power) as it is borne out the horn. You can also use it to prop your iPhone into a vertical ...