Blocking type synchronizer with a synchronizer hub equipped with an external toothing on which, by means of an according inner toothing, a synchronizer sleeve is hold non-rotatably but slidably along the rotational axis, and a synchronizer ring which can be brought into positive engagement with the synchronizer sleeve, and a dog ring which can be brought, as soon as rotating with the same speed as the synchronizer sleeve, into positive engagement with the synchronizer sleeve, wherein the synchronizer ring forms a synchronizer portion which embodies a male cone surface for frictionally accelerating the dog ring to synchronous speed, and that the synchronizer ring forms a blocker portion, too, with a blocker spline that cannot be passed by the teeth of the synchronizer sleeve before the dog ring and the synchronizer ring have reached the synchronous speed, wherein the predominant portion of the male cone surface of the synchronizer portion 14 extends in direction of the rotational axis L and is positioned inside the dog ring, seen in radial direction, wherein the average diameter of said male cone surface is smaller than the average diameter on which said blocker spline is arranged, wherein the synchronizer hub is equipped with an annular cutout for accommodating a predominant portion of the blocker portion, wherein the axial length from the dog ring to another dog ring of the synchronizer is 32 mm or less, characterized in that directly neighboring to a transition area being an area between the blocker portion and a synchronizer portion, the blocker portion is formed by an inner radial portion that is oriented in a radial direction only, wherein the blocker portion is formed by an oblique portion, wherein the oblique portion is inclined away from the synchronizer hub in direction toward the dog ring, wherein the radial extension of the oblique portion amounts to at least 30% of the radial extension of the complete blocker portion, wherein the blocker portion is formed by an outer radial portion that is oriented in a radial direction only, wherein the male cone is positioned radially below the dog ring and the blocker portion. an external toothing on which, by means of an according inner toothing, a synchronizer sleeve is hold non-rotatably but slidably along the rotational axis, and a synchronizer ring which can be brought into positive engagement with the synchronizer sleeve, and a dog ring which can be brought, as soon as rotating with the same speed as the synchronizer sleeve, into positive engagement with the synchronizer sleeve, wherein the synchronizer ring forms a synchronizer portion which embodies a male cone surface for frictionally accelerating the dog ring to synchronous speed, and that the synchronizer ring forms a blocker portion, too, with a blocker spline that cannot be passed by the teeth of the synchronizer sleeve before the dog ring and the synchronizer ring have reached the synchronous speed, wherein the predominant portion of the male cone surface of the synchronizer portion 14 extends in direction of the rotational axis L and is positioned inside the dog ring, seen in radial direction, wherein the average diameter of said male cone surface is smaller than the average diameter on which said blocker spline is arranged, wherein the synchronizer hub is equipped with an annular cutout for accommodating a predominant portion of the blocker portion, wherein the axial length from the dog ring to another dog ring of the synchronizer is 32 mm or less, characterized in that directly neighboring to a transition area being an area between the blocker portion and a synchronizer portion, the blocker portion is formed by an inner radial portion that is oriented in a radial direction only, wherein the blocker portion is formed by an oblique portion, wherein the oblique portion is inclined away from the synchronizer hub in direction toward the dog ring, wherein the radial extension of the oblique portion amounts to at least 30% of the radial extension of the complete blocker portion, wherein the blocker portion is formed by an outer radial portion that is oriented in a radial direction only, wherein the male cone is positioned radially below the dog ring and the blocker portion. directly neighboring to a transition area being an area between the blocker portion and a synchronizer portion, the blocker portion is formed by an inner radial portion that is oriented in a radial direction only, wherein the blocker portion is formed by an oblique portion, wherein the oblique portion is inclined away from the synchronizer hub in direction toward the dog ring, wherein the radial extension of the oblique portion amounts to at least 30% of the radial extension of the complete blocker portion, wherein the blocker portion is formed by an outer radial portion that is oriented in a radial direction only, wherein the male cone is positioned radially below the dog ring and the blocker portion.