A4Tech Battery Free Wireless Optical Mouse NB-30 review

Wireless mice offer freedom of movement by eliminating the cord that tangles its way to the back of a computer. However, the batteries that power them are heavy, costly (both monetarily and environmentally) and have a habit of suddenly expiring. A4Tech's NB-30 seems the ideal mouse then; no cord, and no batteries either.

The mouse derives its energy from the accompanying mouse pad, using electromagnetic induction to convert the pad's local electric field into current. Consequently, the mouse can't stray from the pad, which is itself powered through a 1.5m USB cable. The pad also houses the receiver for the mouse's RF signal, and A4Tech boasts that 100 NB-30 mice can be used in a room without any interference.

The mouse is short on frills - no navigation buttons, for example - but has a comfortable scroll wheel. Extended use allayed our initial fears that the 155 x 205mm pad might prove too small. Also, though the optical sensor's resolution is quoted at only 670dpi (800dpi is the norm), we found no precision problems - even when gaming.

The electrical field precludes use on metal desks or within 20cm of CRTs, and the 1.5m cable for the pad may be too short for floor-bound tower systems. But the NB-30 offers freedom not only from wires but from batteries too.