A stabilizer serves for stabilizing a link of a three-point suspension system of an agricultural tractor. The stabilizer has at least one telescope consisting of a tube and a piston held displaceably therein. Said tube and piston are coupled elastically by at least one spring. The piston is designed such that it can be adjusted in length by means of at least one thread. In order to retain the telescope, the stabilizer has at least one pivotably held retaining clip. In a retaining position, said retaining clip engages over an abutment of the piston whereas, in a release position of the retaining clip, the piston can be freely moved. In order to obtain simple handleability of said stabilizer, the abutment is formed by at least one substantially rotationally symmetrical disc. The piston length can therefore be adjusted in or in the vicinity of the retaining position.