Klipsch RB-10 4-Inch Two-Way Bookshelf Loudspeaker (pair) Has both a back-panel keyhole for on-wall mounting and a threaded insert for attachment to popular adjustable wall and ceiling brackets FREQUENCY RESPONSE - 90Hz-20kHz +/-3 dB SENSITIVITY - 90dB @ 2.83V / 1 meter POWER HANDLING - 50 watts maximum continuous (200 watts peak) NOMINAL IMPEDANCE - 8 ohms compatible