Stabilizer for a lower link of a three-point hitch of a tractor, comprising a first stabilizer member and a second stabilizer member connected to the first stabilizer member by a spring mechanism which allows a longitudinal movement between the stabilizer members, wherein the overall length of the stabilizer is adjustable by rotating the stabilizer members against each other. Furthermore, a blocking means is connected to the first stabilizer member, wherein the blocking means can be moved into a closed position in which a longitudinal movement between the stabilizer members is restricted. The first stabilizer member comprises a rotation-symmetric locking collar which engages the blocking means in the closed position such in that a longitudinal movement between the stabilizer members is disabled, wherein a rotation between the stabilizer members is lockable by a safety means, wherein the safety means comprises a spring clip engaging a recess formed in the circumference of the locking collar.