Not a daft question at all. Paulm gave the correct answer.
It's a Mini Gripper chuck from Craft Supplies (no longer available it would seem), which came in either 1 or 2 morse taper versions or with a 3/4"x16 thread.
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http://www.craft-supplies.co.uk/
I use the threaded version to turn 12" out of round blanks (started with tailstock support). I regularly use it to turn 6" to 9", natural edged, oval bowls & highly recommend it for its gripping power in both wet & dry woods.
IIRC it requires 1 1/4" (32mm) recess cut with a forstner or sawtooth bit, to the depth of the jaws. Don't go too deep or you won't get a spanner on the flats to remove it.
I originally had some qualms that the morse taper version might slip in the headstock when turning out of balance pieces but thinking about it, support from the tailstock would probably prevent any slipping or other movement.
I would go as far as saying that IMHO the grip on this chuck is so good that it is completely suitable for a beginner.
HTH
Robbo