-Variant of 'the spring' of prototype 10 and 15: System to determine electrically if there's still water in the bowl
-Better stability, more reliable 'spring-system'
-Makes use of a PVC-tube piston with resilient material, some 'silicone molds' here. (Variant of spring, prototype 17)
Expected +:More reliable 'spring system'
Expected -:Too weak resilience
Tested +: Better stability
Tested -: ?
user experience: /