Heike you can find Waterpiks at Harvey Norman if you want to see one before buying it, I bought mine at Chemist Warehouse, it was cheaper.

Cheers, Dave (OzMojo)
19Feb2014 Diagnosed T2N2bM0 P16+ve SCC Tonsil.
31Mar2014 2 Cisplatin, 70gy over 7 weeks (completed 16May2014)
11August2014 PET/CT clear.
17July2019 5 years NED.