The figure shows the version WR-DI-PG 21 and WR-DA-PG21

Assembly instructions for Pg16 corrugated pipe
a = Corrugated screw connection
B = Corrugated pipe
c = Opener
Installation note:
Cut the corrugated pipe in the groove to retain a round shape for insertion. The lighter seal (not depicted in the illustration) is positioned in the corrugated pipe screw connection below the safety latch. The darker outer seal (not depicted in the illustration) is placed over the corrugated pipe screw connection from outside. The corrugated pipe is then pushed as far as possible into the corrugated pipe screw connection and clicks into place. The screw connection is opened by placing the yellow corrugated pipe opener with force between the safety latch and the corrugated tube and the corrugated pipe is then pulled out.