The FrSky X14 radios are a great choice for a modern, highly flexible and powerful radio for use with RC submarines. The units have built-in twin 2.4gh antennas, and the packages from the Nautilus Drydocks also includes the R9M 900mhz transmitter add-on as standard. 

Pair these radios with the R9SX receiver to power your submarine on and under the water!
 
ERGONOMIC, COMPACT & FLEXIBLE DESIGN
In alignment with the form factor concept of TANDEM X18, the TWIN X14 has been crafted to enhance its portability, reduce weight, and streamline its design. The ergonomic layout ensures that the momentary buttons, shoulder sliders, and switches on the top are effortlessly accessible.
 
The TWIN X14 offers 4 customizable buttons, thoughtfully placed at the radio panel center for real-time and frequent operations. Take, for instance, when flying an RC glider, to configure these buttons as additional Trim functions by ETHOS, these buttons become invaluable for on-the-fly adjustments then, allowing pilots to adapt the angle of the flaps/surface according to the real-time air environment.
 
BUILT-IN FLASH STORAGE AND RECHARGING SYSTEM | STAND HOLDER ATTACHABLE STRUCTURE DESIGN
Eliminating the need for users to fret over storage decisions, the TWIN X14 boasts built-in 128MB flash storage, providing ample space for your file storage requirements. Its practicality extends to a battery bay accommodating a 2600mAh Li Battery, easily replaceable and featuring a Type-C port for recharging.
 
Further enhancing its user-friendly design, the TWIN X14 introduces an attachable and foldable structure on the rear shell. This design allows for the easy installation of an additional stand holder accessory, transforming the X14 not only can be conveniently carried but it can also to be positioned anywhere, offering operational flexibility without having to hold the radio in your hands.