Kensington picked a pair of ultra-low power Nordic Semiconductor nRF2401A and nRF2402 2.4 GHz ISM (Industrial, Scientific, and Medical) band transceivers for its Wireless Presenter with Laser Pointer. The ultra-low power performance of the transceivers allows a pair of AAA cells to power the wireless link for over a year under heavy usage conditions and provides a 20 m (65-ft) operating range even when obstructions such as people or furniture are in the way. Kensington picked the 2.4 GHz transceivers over traditional 27 MHz devices because of security and immunity to interference. The nRF2401A and nRF2402 use a frequency agility protocol based on Gaussian Frequency Shift Keying (GFSK). Should interference on the transmission channel be detected, this spread spectrum technique allows the transceiver to hop between multiple channels. The nRF2401A and nRF2402 employ a lightweight protocol that only requires the resources of a low-cost external four- or eight-bit microcontroller (MCU), easing the design process. The Kensington Wireless Presenter with Laser Pointer is one in a series of Kensington products released over the last four years that use Nordic Semiconductor 2.4 GHz transceivers.