Multi-part hot-water bottle safety closure, comprising at least one closure part having an external screw thread for screwing into an internal screw thread of a hot-water bottle, and having a first force transmission element for transmitting torque for screwing the closure part into the internal screw thread of a hot-water bottle to water-tight close the hot-water bottle and for unscrewing the closure part out of an internal screw thread of a hot-water bottle; and a manual actuating element having a second force transmission element for introducing the torque required to screw and unscrew the closure part into the internal screw thread of a hot-water bottle, wherein the first force transmission element and the second force transmission element being designed to correspond in such a way that the closure part and the manual actuating element can be releasably coupled to one another by forming an operative connection, wherein the first force transmission element is designed as an internal force transmission element and is formed by surrounding wall portions, wherein the second force transmission element is designed to penetrate at least in sections into the internal force transmission element, wherein at least one part of a penetration area of the closure part, into which the second force transmission element can be inserted, is delimited by an enclosing wall which completely surrounds the penetration area, wherein the closure part comprises a completely circumferential collar, wherein the collar forms an abutment for limiting the maximum screw-in depth and a circumferential sealing element, characterized in that the circumferential sealing element is formed as an elevation with a curved contact surface and is an integral part of the collar and thus of the closure part and wherein the collar is formed by a collar wall having a thickness of at least 2mm in the longitudinal direction L of the closure part, and wherein the collar wall extends orthogonally to the longitudinal direction L, wherein the closure part and the manual actuating element are injection molded parts. comprising at least one closure part having an external screw thread for screwing into an internal screw thread of a hot-water bottle, and having a first force transmission element for transmitting torque for screwing the closure part into the internal screw thread of a hot-water bottle to water-tight close the hot-water bottle and for unscrewing the closure part out of an internal screw thread of a hot-water bottle; and a manual actuating element having a second force transmission element for introducing the torque required to screw and unscrew the closure part into the internal screw thread of a hot-water bottle, wherein the first force transmission element and the second force transmission element being designed to correspond in such a way that the closure part and the manual actuating element can be releasably coupled to one another by forming an operative connection, wherein the first force transmission element is designed as an internal force transmission element and is formed by surrounding wall portions, wherein the second force transmission element is designed to penetrate at least in sections into the internal force transmission element, wherein at least one part of a penetration area of the closure part, into which the second force transmission element can be inserted, is delimited by an enclosing wall which completely surrounds the penetration area, wherein the closure part comprises a completely circumferential collar, wherein the collar forms an abutment for limiting the maximum screw-in depth and a circumferential sealing element, characterized in that the circumferential sealing element is formed as an elevation with a curved contact surface and is an integral part of the collar and thus of the closure part and wherein the collar is formed by a collar wall having a thickness of at least 2mm in the longitudinal direction L of the closure part, and wherein the collar wall extends orthogonally to the longitudinal direction L, wherein the closure part and the manual actuating element are injection molded parts.