Dayton Audio 0.30mH 20 AWG Air Core Inductor Crossover Coil 
Dayton Audio 0.40mH 20 AWG Air Core Inductor Crossover Coil 
Dayton Audio DMPC-3.0 3.0uF 250V Polypropylene Capacitor
Dayton Audio DMPC-3.0 4.0uF 250V Polypropylene Capacitor
Parts Express Red Perforated Large Hole Crossover Board Pair 3.5" x 5"

Wire
Soldering Iron

I use this corssover for the following drivers:
Peerless by Tymphany TC9FD18-08 3-1/2" Full Range Paper Cone Woofer (8 ohm woofer)
Dayton Audio ND16FA-6 5/8" Soft Dome Neodymium Tweeter (6 ohm tweeter)