Kind thanks to Joost from Appelboom Pennen, who sent me this new TWSBI Diamond 580AL Turquoise.  If you shop at Appelboom, use the discount code in the banner below (‘friend’) for 10% off your purchase – excluding Montblanc.

Measurements
Length (capped): 142.8 mm/5.6″
Length (uncapped): 130.8 mm/5.1″
Length (posted): 175.3 mm/6.90″
Diameter (barrel): 12.5 – 14.3 mm/0.50″ – 0.59″
Diameter (section): 10.2 – 11.1 mm/0.40″ – 0.44″
Weight (all): 24 g
Weight (cap): 4 g
Weight (body): 20 g