Clip for upholstery panels. Where the lozenge-shaped eye meets the U-shape, note the little "foot" where the lower arm of the lozenge touches the U. This foot is not attached to the U, but moves freely. When this clip is mounted properly, this "foot" should be positioned such that a flat tool can be inserted between uphostery panel and the fixed part of the body, and push against this foot (in this picture that would be in upward direction) such that the lozenge becomes somewhat smaller and pops out of the fixed body part where it was pushed in. Spare clips are easily obtainable, e.g. from BAS International.