Siro was a sub brand of Oris (the name is reversed), and this large men’s watch is a nice survivor.


We are struggling to find an awful lot of information about Siro.  We do know they were registered in 1925, so this watch must be later than that.  The simple pin pallet movement doesn’t feature any shock protection that began to be widely used from the 1940’s onwards, and with this combined with the styling and other dating clues like fixed lugs we think this watch was produced circa 1935.


Both the dial and the acrylic have faded to a yellow colour, but it is even and probably points to the crystal being the original item – that is pretty remarkable for such an old watch.  The movement is working well, but will all pin pallet movements you will not get the same accuracy as more expensive Swiss lever watches.  You also have the extra noise of a pin pallet watch ticking away on your wrist.  The two piece case has a few thin spots of chrome but is quite dent free.  The case is also quite large for the period, and wears well.  The leather strap is new.

This watch will be supplied with a presentation box and our Certificate of Authenticity.

Please see the HD video for more detail.


Width with crown  34.2 mm

Width without crown  32.0 mm

Between lugs  16 mm

Lug to lug length  38.9 mm

Case Thickness  11.5 mm

Bracelet maximum length   n/a

All sizes are approximate.

Included with this watch is a 1 month guarantee and free delivery to UK addresses.  If you live outside the UK we can still deliver to most countries.  Please see our Worldwide Shipping information, or Contact Us.