Currently, AKA produces only DD coils. 

AKA coils have different sizes and frequencies. This is due to the need to use different equipment for different types of search and conditions. 
For example, the small diameter of the coils must be used in littered (metal waste) areas. The more debris, the smaller the diameter of the coil. 
If the targets are small, then you need to take a high frequency coil. 
Below are the sizes of AKA coils and the frequencies with which such coils are produced 

• 6 ″ at 7, 14 kHz 
• 6x10 ″ at 7, 14, 20 kHz 
• 10 ″ at 7, 14kHz 
• 9x12 ″ at 3, 7, 14, 20 kHz 
• 13 ″ at 3, 7 kHz 
• 15 ″ at 3, 7 kHz 

AKA coils at 3 frequencies 

Separately, it is worth noting coils at 3 frequencies. Switching is performed by a toggle switch on the connector on the coil itself, see photo: 

AKA coil 9x12 "3F 
The following coils are currently available for purchase: 
• 9x12 ″ at 3 frequencies (3, 7, 14 kHz) 
• 13 ″ at 3 frequencies (3, 7, 14 kHz) 
• 15 ″ at 3 frequencies (3, 5, 10kHz) 
The frequencies in them are switched by a toggle switch located on the coil near the connector. 

AKA coils at 2nd frequency 

Since 2017, AKA has launched the production of 2 frequency coils. Frequency switching occurs by the tumbler on the coil itself. 

AKA coil 9x12 "2F 
In particular, the following coil sizes and frequencies are available: 
• 6x10 2F - coil at 6 and 14 kHz 
• 6x10 2F - coil at 12 and 20 kHz 
• 9x12 2F - coil at 6 and 14 kHz 
• 9x12 2F - coil at 12 and 20 kHz 
• 13 2F - coil at 6 and 13 kHz 
• 15 2F - coil at 3 and 7 kHz 
The manufacturer guarantees the possibility of short-term immersion of such a coil in water. 
AKA coil warranty - 1 year 

AKA mono coils

for work in a littered area

• 8 - coil 7 kHz 
• 8 - coil 14 kHz 
• 8 - coil 20 kHz