This is a handmade pickup for my double bass. It's the type that you insert into the gap next to the bridge. The photo is an image. In reality, it's better to insert it a little further in. If it's too tight and in a state like the photo, you'll need to shave down the bridge feet. The sensor is a little over 5mm thick. It's new, only tested for functionality, and has a handmade feel. It will be secured to the tailpiece with zip ties or similar, as shown in the photo.