Check the listing for details. Hermle 340 341 350 351 New Brass Replacement Clock Key Size 8 4.25mm. Condition: New. Listed at 14.95 USD. Here's a replacement key for your Hermle 350, 351, 340, and 341 series clock movements. It will also fit some Seth Thomas, Gilbert, Sessions, Ingraham, Waterbury and other antique clocks. Brass key with winding end in size #8 or 4.25 millimeters. This key fits many antique American clocks as well as Hermle 340 and 341 movements. To confirm the key is correct size measure the square winding shaft. The square opening of this key is 4.25 millimeters. Free USPS First Class Shipping! Please email if you have any questions. International Buyers – Please Note: Import duties, taxes, and charges are not included in the item price or shipping cost. These charges are the buyer's responsibility. Please check with your country's customs office to determine what these additional costs will be prior to bidding or buying.