Introduced last year, the Montblanc Heritage Perpetual Calendar was the most affordable perpetual calendar – priced at US$12,800 in steel – from a major brand. For Watches&Wonders 2015 that takes place in Hong Kong next month, Montblanc has jazzed it up with a grey sapphire dial that shows off the gears and levers that keep the calendar perpetual.

The case is red gold, 39mm in diameter, with sapphire crystals front and back. It has clean lines, and a polished finished all round. Lightly tinted a smoky grey, the dial has facetted red gold-plated indices along with red-gold plated hands. All the of the perpetual calendar module is visible, including the snail cam for the date indicator at three o’clock.

At six o’clock the moon phase disc is shown in its entirety, but the lower half is engraved with a concentric guilloche to mark it out from the upper half that show the current age of the moon.

Able to keep track of the correct calendar till the year 2100, the perpetual calendar module is made by Dubois Depraz, a complications specialist that supplies the same module to several other brands in a similar price range. And the base movement for the watch is the robust but common ETA 2892.

That’s why last year’s solid dial version of this is the most affordable perpetual calendar from a mainstream brand, priced at US$12,800 in steel and US$21,600 in red gold. The price of the sapphire dial version is only slightly higher, at S$31,500 or €19,900 (equivalent to US$22,900).