The Diatone 2019 GT R249+ is one of the newest series of micro quadctopers from Diatone that is built around the Mamba mini f4 stack.
The full range from smallest to largest includes:
As you can see there is a high degree of modularity - for all except the largest they share the same 1105 5500kV motors. All sizes feature a 3mm thich carbon baseplate except for the R239 which uses and injection moulded plastic chassis and prop-gaurds. All models share the same injection moulded lightweight canopy and mamba mini f4 stack.
I've chosen to review the R249+ since my experience with micro quadcopters has lead me to believe that this is the 'sweet' spot in terms of performance and staying small and discrete when flying.