The Four Square was a relatively short-lived, rather over-designed mechanical pencil, hence its relative rarity.  It used square leads and this version - before they went to the rather bulky ergonomic grip design - is the most eye-catching.  It lasted from around 1935 - 1936.  It has two significant features:

1.  A transparent square barrel, with a red dot in the lead propelling mechanism visible to the user.  This red dot is aligned with the end of the piece of lead in the barrel - giving you an indication of how much lead is left.

2.  A fantastically designed cap.  Unscrew it to access the lead storage chamber.  Screw it back on and pull the cap bushing off.  Then reverse the cap bushing - and push it back on - this pushes out the eraser.  Talk about interactive.

This was a relatively entry-level priced pencil - but its design was not entry level and so production was not cheap.  The Four Square was outmanoeuvred by cheaper models which did the same things much more simply.  The Four Square lasted only about 6 years in 3 versions before disappearing.  This is the "middle" years version.

To have such a pristine example, boxed and with instructions and vintage leads, is very rare.  Additionally, Four Square did not appear in Wahl catalogues of the time - so the only history I can find of its advertising is shown in my photographs (an advert from 1935).  It does seem to be a bit of a specialist collectors' item.

This pencil is a single unit, square-faced barrel of golden / pale green coloured plastic, with the diagonal brick print embedded in the plastic (not surface printed).  The plastic is in excellent condition - no cracks, damage, gouges etc.  There is light handling wear, micro scratches visible under magnification.  The metal clip and lead cone are bright and show no brassing or wear.  The clip is stamped "EVERSHARP" and "MADE IN U.S.A.".  The lead cone has 3 chased lines of finger-grip (it is the cone which is turned to propel / repel the lead) and has an arrow (I cannot work out why).

The cap is in black plastic and excellent condition.  Stamped "SQUARE 4" in a logo design and "GENUINE √√ EVERSHARP".  The top of the cap has a metal disc.  It unscrews cleanly from the barrel on a clean aluminium post, to reveal the lead storage chamber.  Screwed back on, the plastic bushing can then be pulled off the aluminium post, the cap is then flipped round and replaced "upside down".  When pushed home the eraser is propelled out.  The original eraser is in situ, clean and only lightly used (if rather hard).

The box is in good condition, showing more signs of age related wear than the pen, most especially to its corners.  However it is entire, and printed EVERSHARP FOUR SQUARE, a "4 PENCIL" logo and "MADE IN U.S.A.".

Original instructions are entire with one rip, and they have the London address of Wahl Eversharp on the bottom.

An unopened tube of 1930s vintage Four Square leads is also included.

Dimensions (approximate):  15.2cm long, 0.8cm wide, 14.5g

I will send this pencil carefully packed via signed-for Royal Mail, and please note if you are buying from outside the UK, this pencil will be delivered by the eBay Global Shipping Programme (GSP) which will take around 10 days to get to you.