The present disclosure is directed to a sanitary insert unit, configured for insertion into a discharge fitting. The insert unit includes an upstream sieve connected to a throughflow regulator. The throughflow regulator includes a control gap and a throttle body that deforms under pressure to regulate throughflow by varying an opening size of the control gap. The sieve and throughflow regulator are arranged upstream of a jet diffusor which includes a plurality of radial openings. The sieve, throughflow regulator and jet diffusor are arranged to be, at least partially, received within a housing. The ratio of the overall height of the insert unit to the height of the height of the assembled sieve and throughflow regulator is approximately 2.7:1.