Double-Knock mechanism

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Some double-knock pencils. Left to right: three Niji Grip 350DX (the black one is a vintage model), two Niji Grip 0.9mm, a Pilot Delful The Shaker, and a Serve Swell

Double-knock or vanishing point (also dual action), is a particular type of mechanism that allow the tip of a mechanical pencil to fully retract inside the body of the pencil. In a double-knock pencil, a deep click of the push button extends the whole tip section, while further short clicks allow the lead to come out (like a regular mechanical pencil). In order to retract back the tip (when it's in the extended position), usually another deep push of the button is needed.

Double-knock pencil models[edit]

Brand Model name Additional Features
Pilot Vanishing Point Lead hardness indicator
Pilot Automac Auto advance mechanism; metal body
Pilot Delful The Shaker Shaker mechanism with lead lock when the tip is retracted
Pentel Graph Gear 1000 Spring loaded clip to retract the tip; metal body; lead hardness indicator
Pentel Technica-X
Pentel Flex Fit Spring loaded clip to retract the tip; ergonomic rubber grip (also customisable in the Flex Fit II)
Pentel TranXition Spring loaded clip to retract the tip
Rotring Rapid Twist-extendable eraser
Niji Grip 350DX Twist-extendable eraser
Ohto Horizon Auto advance mechanism; side button to retract the tip; metal body
Paper Mate Apex Twist-extendable eraser
Aristo DK2 Twist-extendable eraser
Serve Swell Twist-extendable eraser
Cult Pens Cult Pencil Side button to retract the tip; metal body
Stabilo Microtom 3365