The PicoScope 4444 uses a standard D9 connector in a custom pin out. So for customers who wish to use existing single-ended BNC probes, BNC current probes, coax cables and so on will require an adapter. The TA299 is a dual BNC to D9 adapter to cover differential applications where signals are presented as two BNCs. 
 Applications: 
-  Allows use of our new AC Flex current probes to enable power quality applications. 
-  Allows the PicoScope 4444 to be used as a standard oscilloscope, or have a mix or single ended and differential signals 
-  NOT CAT rated