Quantity   Component name
2 × XBee Pro S1 or XBEE Pro S2C (S2C is the best) I am currently using a pair of the XBee Pro S1 transceivers
1 × Teensy 3.2 Board Arduino compatible mini board (these are awesome!)
1 × Teensy 3.1 XBee Adapter Board These are sold by Sparkfun
1 × Teensy Prop Shield Don't buy the LC board, its missing all the important sensor chips
2 × Stand off arduino headers for Teensy board Enough for the Teensy and the Prop Shield to be mounted to the adapter board