Does the job
This is the second time I have replaced this part, the second time being only a few weeks after the first replacement. I'm not sure if this means that the part is of inferior quality or whether I have a bigger problem with the shower (unlikely as I have replaced the shower head and hose at the same time).
The PRD supplied is a genuine product from the manufacturer and to our knowledge have not changed in any way.
If the PRD device is a saftey device for the shower is only activated activated if there is a problem with the shower and it could be down to one of the following:
Shower head is blocked
The inner of the hose has collapsed
The hose was kinked whilst showering
The head and hose have been changed to a non manuafcturer product
You have underlying issues in the shower causing the PRD to activate