Based on the VB-2 kneeboard, but with added extras.
The VB4 has been specifically designed for use when instrument flying.

Along with the regular features of pen pockets, stop watch holder opening, clear plastic cover/flap and external rear pockets, the VB4 includes A5-sized ring binding and 6 clear vinyl pockets down the side of the flight board to hold Aerad, Jeppesen and UK VFR Flight Guide pages and/or document wallets.
The conventional spring-clip is retained, but moved to the right and can be used to hold an A4 or A5-sized navigation log, or to hold-open the relevant plastic wallet in the ringbinder.