The differences between the two units are:
- The 6-in-1 (labeled HD319B) supports 4K60Hz, while the 4-in-1 supports 4K30Hz.
- The 6-in-1 has detachable grips and an extension cord
- The 6-in-1 has an SD/Micro SD slot.
- The metal used in the 4-in-1 is heavier than in the 6-in-1
Other than that, they share the remaining features.