Ohto Horizon 0.5 Mechanical Pencil
The first push on the top button extends the whole lead mechanism out of the barrel. Further pushes then feed the lead as per normal mechanical pencils. To retract the entire tip simply press the button on the side of the pencil once.
There is a replaceable eraser under the push button and it uses standard 0.5mm lead.
Horizon Pencil measures 141mm long, 9mm wide.