Leading Singaporean-based luxury watch retailer The Hour Glass celebrates their 40th anniversary this year and has created a commemorative edition with one of their top independent watch partners: Urwerk.

The Urwerk UR-105 Hour Glass 40th Anniversary Commemorative Edition will be limited to just three pieces and comes in a 39.5 mm wide case that’s inspired by the UR-103 – with a larger sapphire window added to the existing UR-105 design. Additionally, the top plate is crafted in sandblasted bronze (similar to the UR-105 CT Maverick Bronze), which is made from an alloy that Urwerk formulated to be slightly darker than most bronze watches currently on the market, so it will be interesting to see how the watch patina looks as it ages. Blackened titanium is used for the rest of the case.

Underneath the top plate is the 52-jewel automatic Urwerk caliber UR 5.03 which features a wandering hours display by way of four satellites (with three-hour numerals each), visible through the large U-shaped sapphire crystal. The hours pass in turn along a scale of minutes, giving a digital and analog indication of the time. A power-reserve indicator and digital seconds make up the rest of the information on the dial.

On the back is the winding rate control lever which can speed up or slow down the dual air turbines which regulate the automatic winding. You can also use the large crown to hand-wind the mainspring – taken from the UR-200 – located at the top of the case. The maximum power reserve is 48-hours.