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
Alvin Draft-Tec Retrac 4mm drafting tip
Aristo DK2 Twist-extendable eraser
Baile Double Nib 538
Colleen Jib WK-816
Colleen Jib WK-1051
Cult Pens Cult Pencil Side button to retract the tip; metal body
Fuji Corona No. 205-03 Mecha-Pen 4mm drafting tip
Linex DP 1000 Side button to retract the tip
Linex DP 2000 Twist-extendable eraser; 4mm drafting tip
Manufactum Druckbleisift Messing Side button to retract the tip
Niji Grip 350DX Twist-extendable eraser
Ohto Horizon Auto advance mechanism; side button to retract the tip; metal body
Ohto OP-500[1] Spring loaded clip to retract the tip
Olympia Double Knock
Pacific Arc RDP-405
Pacific Arc RDP-605 Twist-extendable eraser
Paper Mate Apex Twist-extendable eraser
Penac Double Knock
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
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
Platinum W-Knock MH-120
Pyramid SP-60 Double Knock
Rotring Esprit double push R5033312 Side button to retract the tip
Rotring Initial R504340
Rotring Rapid Twist-extendable eraser
Serve Swell Twist-extendable eraser
Senator Avantic
Spaper Technic Retro
Stabilo Microtom 3365
Staedtler Retro 778
Staedtler Retro de Luxe 778 25 Premium chromed steel body
Sun-Star W Knock Sharp
Tomato Hidden Nib HN-50
Tombow Protect SH-WPS