Diameter: Approximately 3.5cm. This is a Seiko School Time GT mechanical men's watch for sale ☺︎ It's an antique hand-wound watch with a sharp black face. There may be minor scratches and clear marks from use, including on the glass surface, but as you can see, it's in a reasonably clean condition. Please examine the images carefully. The belt has been replaced with a new, non-original leather belt that looks natural. As this is a used hand-wound watch, I cannot guarantee future operation, but it was working normally when I wound the hand-winding screw (crown) at the time of listing. Quick change is currently working fine. * I do not perform any adjustments such as an overhaul. There are no accessories. I am very sorry, but please absolutely, absolutely, absolutely refrain from purchasing if you are unfamiliar with used items, are overly sensitive, do not understand the above explanation, or have any concerns. Mercari is a platform for private sales. This is a used item in its current condition, and it has been inspected by an amateur (there is no 100% guarantee... the condition in the images is everything), so please understand. This is a slightly rare Seiko School Time GT antique watch. Please make it a treasured item... #Seiko #SEIKO #SeikoSchoolTime #SEIKOSCHOOLTIME #SCHOOLTIME #SeikoHandWoundWatch #HandWoundWatch #MechanicalWatch #SeikoTomony #Tomony #SeikoMechanical #SeikoSchoolTimeGT Movement: Hand-wound