This is an 18K solid gold model, with "18K 0.750" indicating the gold purity, hallmarks, a serial number, and the model number engraved on the inside of the case back. Hallmarks are also present on the underside of the case lugs. Model number: R2500 ⭕️Guaranteed authentic. We will accept returns if the item is found to be a fake. The dial has a radial finish, with delicate lines that give it a luxurious feel, and it's a very clean example considering its manufacturing year. The 12 o'clock position on the dial features the inscription "International Watch Co" in cursive, giving it an antique feel. The indices are Roman numerals, and the hands are black, providing good visibility. The movement is a hand-wound "Cal.422". "Cal.422" is a two-hand movement that omits the second hand from the Cal.402. It's a movement with a large, split bridge, showcasing the characteristic IWC aesthetic. The crown has a diameter of 3.8mm, making it easy to grip and operate. There is little wear on the edge of the crown, which is common for hand-wound models, and it is in beautiful condition. The case diameter is 33.7mm, which is small. The buckle is original (gold-plated). ・Please be sure to check the images before purchasing regarding the condition. ・Please refrain from purchasing if you are sensitive to the condition of old watches. ・I am not an expert on watches. If you would like additional images, please feel free to ask in the comments.