I would recommend the Spektrum DX6i transmitter (controller) or the later Spektrum DX6 transmitter. The DX6i comes with a rechargable feature to conserve batteries and also has 6 radio channels.
You can buy the DX6i through this link: http://www.bhphotovideo.com/bnh/controller/home?O=&sku=1048130&gclid=CjwKEAjwiumdBRDZyvKvqb_6mkUSJABDyYOzqrIhGyHgkS8gemjlNwTqn49LXFOMojzl7b1d9CPd3BoCtsnw_wcB&Q=&is=REG&A=details.
Note: Not all DX6i models are rechargeable, but if you want to be able to recharge your transmitter if it isn’t able to be recharged through the model, you can buy rechargeable batteries.
The DJI site also advertises the DT7 transmitter, which comes with the reciever. You can buy it through this link: http://www.dji.com/product/dt7-dr16-rc-system.
