Now since P3S and 4K used a 5.8Ghz and 2 2.4Ghz, installing 3 amps on the remote is practically weightlifting and you will soon get a cramp after the 3rd battery (I'm not into tripod yet). So I have been looking at the market and I found this: 5W double port 2.4Ghz amp. I searched for any thread about this but didn't find one. I think this is a very good amp for pro/adv as well. It only needs 1 DC input instead of 2 if you use 2 Sunhans 2.4Ghz. I just need to make this detachable and can use them for Standard/4K or Pro/Adv in case I upgrade. What do you guys think? Its $105 at my local e-commerce (and I don't have to pay import duty) I just need to find a good panel to hold it and the lipo/li-ion battery.