The TX-A1243 is a Transmission Kit specifically designed for Apple USB Keyboard (A1243). It can make your USB Keyboard (Apple A1243) to be a Bluetooth Wireless Keyboard. You don't need to buy another keyboard. It saves your money and our planet. Furthermore, TX-A1243 with multi-host support can work with Mac, iPad or other Bluetooth-enabled Macintosh computer in between. **Wireless Specification - Tx Technology : Bluetooth wireless technology (Broadcom Bluetooth chipset) V. 3.s0 - Antenna/ Antenna Gain : PCB Antenna / -0.99 dBi - Frequency/ Channels : 2.402GHz ~ 2.480GHz/ 79 channels - Modulation : GFSK (Differential Phase Shift Keying) - Output Power : Normal Mode (GFSK): -0.61 dBm - Data Rate/ Sensitivity : Up to 2.1Mbps / < 0.1% BER at â??70dBm - Operating Range : Up to 4 M (Free space) **Electronic Specification - 3 LED Indication : Pairing in Green / Connection in Blue / Power charging in Red - Multi-Device Support : Support up to 4 different Bluetooth enabled Devices - Switch/ Button : 1 x power switch / 1 x pairing button - Charging Port : Micro USB Port - Input Power : 3.7VDC, 1900mAh (built-in Li-ion Battery) - Compatibility : Compatible with Mac OS 10.5.8 or later; Apple iOS - Physical Dimension/ Weight : 410.0 (L) x 75.0 (D) x 15.0 (H) / 150g (N. W.) - Box Dimension/ Weight : 430.0 x 102.0 (D) x 21 (H) / 255g (G.W.) - Accessories : 1 x Micro USB charging cable, 1 x User's manual