The invention relates to a core for winding self-adhesive, coated, strip-like materials, characterized in that the external contour of the core is formed from at least one substantially round self-contained segment whose ends converge in an edge, wherein a) the round segment is convex shaped in relation to the core axis, b) the surface normals of the round segments are oriented substantially orthogonal to the core axis, c) the edge is oriented substantially parallel to the core axis and the core has an inner recess so that the coil and the core can be inserted on commercially available adhesive strip reels having a specially cylindrical core gripper.