You Do The Math Watch. Geek Chic. Maths Watch for Geeks. Unusual Gift. Genuine Leather Strap Imported Genuine leather strap. Silver tone case. Crystal Glass. Stainless steel back. Supplied from the UK in a black slim-line presentation box Face diameter - 32mm. Watch casing diameter - 38mm. Width - 9mm. Silver tone hands Quartz movement. Water resistance classification - splash proof