The Drening cap is the only one that permits both the entry and the exit basin closures. It has to be hooked by interlocking, In the case it doesn’t hook at one side, rotate it by 180° and try to hook it again. Each cap is made to be perforated and the pipes standard diameters are indicated with a stamp. 

The pipes can be inserted both at the top and at the bottom of the cap.

The cap marked diameters are made for these pipes: 
Ø 60 mm (minimum diameter)
Ø 110 mm
Ø 120 mm
Ø 160 mm
Ø 200 mm
Ø 300 mm
Ø 320 mm (maximum diameter)