Hello loon
What you need to find is a resistor :
120 ohms value
able to sustain CONTINUOUS 0.51w dissipated power
so my guess is to go for a 1w or 2w resistor.
Since Freetrack isn't a hi-perf electronics setup, you can use almost any resistor type, you don't need to go for a particular res type (precision res, ...)
So look for a 120 ohms 1W or 120 ohms 2W resistor, the cheaper the better.
for example you can use maplin's reference :
D120R found , on
this page
cya