its the normal jenvey / colvern / webash sensor allan, comes with all the jenvey ITB kits. You can buy them from jenvey or from RS if you're not bothered about the round 3 pin econoseal connector thats probably on it. They fail a lot, wires snap on entry to the sensor.
But when you install a new one it's essential you hook the laptop up and re-calibrate it. If you don't you'll spend hours adjusting the bugger until it runs right, and even then you can't be sure the fueling is right.
Is it emerald ? The software is free, the leads are a few quid.
http://docs-europe.electrocomponents...6b8008fc9a.pdf