Short answer
The replica Portofino Hand-Wound 35 is a 35 mm manual-wind watch sold by replica factories. IWC does not list a 35 mm Portofino Hand-Wound. The genuine Portofino Hand-Wound Eight Days has a 45 mm case (ref. IW5101, IW5102). A 35 mm version is a fantasy size made for smaller wrists. Movement, finish, and price vary by factory and batch.
Case size and fit
Case diameter: 35 mm. Lug-to-lug: about 41 mm to 43 mm, based on seller listings. Thickness: 9 mm to 11 mm. Genuine thickness is 12 mm at 45 mm diameter. Stainless steel 316L. Water resistance: 30 m claimed, 0 m tested. Weight with strap: 55 g to 70 g. The small size suits wrists under 17 cm. A 35 mm hand-wound watch sits flat on the wrist. Lug width: 18 mm or 19 mm. Confirm before buying a strap.
Movement
Genuine IWC caliber 59210 is hand-wound, 30 jewels, 28,800 vph, 8-day power reserve. No replica at this price copies that. Common replica movements: a 21-jewel Chinese manual wind (ST17 base) or an automatic with the rotor removed. Power reserve: 36 to 42 hours. Beat rate: 21,600 vph. Hacking: often no. Hand-winding a rotor-less automatic damages the gear train. Ask the seller for the movement name and a photo of the back.
Dial, hands, crystal
Dial: white or black, applied baton markers, small seconds at 6 o'clock. Print quality decides the look. Look for a clean IWC and SCHAFFHAUSEN print. Hands: leaf shape, polished. Crystal: sapphire on better batches, mineral glass on cheap ones. Caseback: solid steel or a display back with a decorated movement. A solid back hides the movement.
Strap and clasp
Most units ship with an 18 mm or 19 mm alligator-grain leather strap and a steel pin buckle. Strap quality is low. Swap it. A 35 mm case needs a 16 mm to 18 mm taper to look correct.
Price and checks
Price range: $120 to $350. Above $350, the movement and case finish should include sapphire and a 28,800 vph movement. Checks: crown action, second-hand alignment, marker alignment at 12, date or no date, rotor noise, and strap holes. Ask for a timegrapher photo. Return policy matters more than the brand name on the dial.
Care
Wind once per day at the same time. Do not overwind. Keep it away from water. Service cost often exceeds the watch price. Treat it as a wear item.