This is a bold and striking fashion collar/choker made from sturdy stainless steel. It has a minimalist, sleek design with a polished finish. The key feature is the small, integrated hex screw on the side that acts as a lock – when tightened, it secures the collar closed, and it's opened with the included hex key. It also comes with a removable O-ring at the front; you can take it off for a simpler choker look or keep it on for a more distinctive style. The collar is handmade, so the internal diameter may vary slightly (by about 2mm). It's crucial to measure your neck carefully before ordering. The listing provides circumference options (converted from internal diameter): for example, a 15cm internal diameter equals about an 18.5-inch circumference. We recommend sizing up if you're between sizes. Please be very careful when closing it, as the hinge can pinch. The metal is 4mm thick and 17mm tall, giving it a substantial feel. It includes a spare screw. This piece is intended as a fashion accessory for gothic, punk, or alternative styles and is popular in certain subcultures. It's not designed for strenuous activities.