Genuine Harris Bipod 9-13" Swivel model SL I think.
These are the original and best there are many copies but everyone knows Harris are the ones to have.
Only selling as I have moved over to the notched legs versions as my hands are not so good these days and I find the thumbwheels difficult to operate.
Smooth leg with thumb wheels for infinite adjustment.
These where £140 new in the gunshop I was in the other day.
Grab yourself a bargain £68 posted