Pocket audio players, which can store several hours of music, are becoming hugely popular, largely because they are small. The digital audio player Card Rec RM-300M, made by Japan's Seagrand, stands out from other portable audio players because it is the size of a credit card, so it can fit in a wallet. The Card Rec has all the functions of an MP3 player - it can connect to a PC and have MP3 files downloaded to it. Its MP3 encoder is based on the one in its popular predecessor, the audio-cassette tape-shaped Ravemetal RM200M, and handles MP3 and Windows Media and Astound Dynamic audio files. It comes in three capacities - 128 megabytes of random access memory, 192 and 256MB Ram. That capacity is a bit small for people eyeing a 20 gigabyte Apple iPod but the Card Rec's selling point is really its portability. Another grouse is it works only with Microsoft Windows so there is no Mac support. It has a line out socket to connect to a CD player, speakers or hi-fi system and connectivity to the PC is through a USB 1.1 port. The power cable is a bit bulky and Seagrand should consider integrating Bluetooth into the Card Rec for wire-free listening.