A delivery system for dispensing an active substance in spray form comprises a head unit including a valve in communication with a dispensing nozzle, a first reservoir containing a fluid propellant, and at least a second reservoir containing the active substance. The sorting assembly comprises a plurality of gates forming a visual barrier, each gate leading to a separate animals area. The allele specific oligonucleotides are resistant to proof reading activity from a polymerase and may be extended in an allele specific manner by a DNA polymerase with a functional 3\u2032 to 5\u2032 exonuclease activity. Due thereto, it can be made such that the second energy absorbing portion does not interfere with the inner peripheral surface of the insert-through hole.