Rekon35 is a cool concept, but I had issues with the battery tray not maintaining contact and the model would reboot mid flight. remix flattens out the battery tray to allow use of the original 2s battery holder as intended and adds elevation to use a battery strap to secure the cells in place.  You also have the option to use a 3s lipo battery instead for better performance but shorter flight time.  

short version simply has the sides flattened out.  battery strap needs to be installed prior to securing the plate.  (PITA to replace)

tall version also raises the profile by 3 mm,  squares off the base, enlarges the screw holes by .5mm and allows more room to insert a battery strap without taking the quad apart to do so.