Ultrasonic transducer used in measuring and automation technology, wherein said transducer is designed to determine or monitor a measured variable, said transducer comprising: a transducer element designed to transmit or receive ultrasonic signals; an adaptation element acoustically coupled to the transducer element, with a first side facing towards the transducer element and a second side facing away from the transducer element, wherein the adaptation element is designed to guarantee an acoustic adjustment between the transducer element and a medium which impacts the adaptation element, wherein the adaptation element has a first longitudinal axis and an axial extension in relation to the first longitudinal axis, and wherein the adaptation element is designed to transmit ultrasonic signals between the first side and the second side of the adaptation element and vice versa, wherein the adaptation element partially fills in each cross-section of the adaptation element in a first subsection of the axial extension, wherein a filled-in proportion in the first subsection increases monotonically along the first longitudinal axis in the direction of the first side, wherein the first subsection comprises at least 60 % and particularly at least 80 % of the axial extension of the adaptation element along the first longitudinal axis, characterized in that in the first subsection the adaptation element has several ring elements, wherein said elements are arranged concentrically around the first longitudinal axis, wherein the monotonic increase of the filled-in proportion is set by an increase in a thickness of the ring elements, and wherein every ring element partially fills in each cross-section in the first subsection, and wherein the ring elements are made from a metal, a glass or a ceramic. a transducer element designed to transmit or receive ultrasonic signals; an adaptation element acoustically coupled to the transducer element, with a first side facing towards the transducer element and a second side facing away from the transducer element, wherein the adaptation element is designed to guarantee an acoustic adjustment between the transducer element and a medium which impacts the adaptation element, wherein the adaptation element has a first longitudinal axis and an axial extension in relation to the first longitudinal axis, and wherein the adaptation element is designed to transmit ultrasonic signals between the first side and the second side of the adaptation element and vice versa, wherein the adaptation element partially fills in each cross-section of the adaptation element in a first subsection of the axial extension, wherein a filled-in proportion in the first subsection increases monotonically along the first longitudinal axis in the direction of the first side, wherein the first subsection comprises at least 60 % and particularly at least 80 % of the axial extension of the adaptation element along the first longitudinal axis, characterized in that in the first subsection the adaptation element has several ring elements, wherein said elements are arranged concentrically around the first longitudinal axis, wherein the monotonic increase of the filled-in proportion is set by an increase in a thickness of the ring elements, and wherein every ring element partially fills in each cross-section in the first subsection, and wherein the ring elements are made from a metal, a glass or a ceramic.