Brand new 5m long Xbox link cable.

Connect 2 Xbox's together to play one-on-one, on seperate TVs.
Will work with any Xbox, whether you have a modchip installed or not.
Works with any game that supports 'system link'(is printed on back of game cover), eg:
Halo
Halo 2
Serious Sam
Crimson Skies
MechAssault
Brute Force
Return to Castle Wolfenstein
Project Gothem Racing 2
Time Splitters 2
Ghost Recon, & Island Thunder
Unreal
Solder of Fortune
Tony Hawks Pro Skater 4
motogp 2
& a lot more

I'm pretty sure all games will require a matching game disk in each Xbox.

Cable is standard cross-over ethernet cable(CAT 5 Enhanced). Xbox's have a builtin ethernet controller, that is used for linking.
Cable can also be used to network 2 PCs (each PC must have a network card, with RJ45 socket - the most common type), without a hub.

Can also be used to connect between your Xbox & computer, for online gaming(via 'Xlink Kai' or similar, rather than using the Xbox Live paid service), Xlink Kai works by tricking the Xbox into thinking it's playing on a local network.
Can also be used to transfer files between Xbox & PC(or another XBox), you'll need software on your Xbox(so will need to have been modified by a modchip/flashed bios/etc) to support this though.
You'll need a network card(or builtin network card) in your PC for this.

Nicely moulded cable, good quality.

'Patch'(non-crossover) cables available at the same price(for same length):
- patch cables can be used for connecting an unlimited number of Xbox's via a hub/switch.
- patch cables can also be used to connect between Xbox & internet(broadband) modem/router, for Xbox Live.