For this project you will need:
3 12v fans
2" of 1/4" Heat Shrink Tubing
1.5" of 1/2" Heat Shrink Tubing
1 2.5mm power jack
1 12v power supply
For the powersupply checkout goodwill you can usually pick one up anywhere between $0.49 to $1.99
Whenselecting your powersupply you should select one that can handle the current needed for all fans.
In my cas 2 of the fans draw .12 A and the third draws .17 A.
So I need a power supply with a minimum rating of (.12+.12+.17) = 410 ma or .41 A
The Pack that i chose is rated at 1.2 A so I am well below it rated capacity.
Step 1: Select Fans and Fasten Together
Once you have selected your fans arrange them into the desired configuration and tie together with 4" zip ties. You could use longer zip ties however they will be wider an may not fit through the fan screw holes.