Double-Knock mechanism
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
| 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 | 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 | |
| You & Me | DBL-KNOCK |