Drilling requirement for P5250 - 25mm
Drilling requirement for twist locks - 12mm

Can user change from using P5250 Maintenance Free Under Counter Water Filter to Twist Locks in future?

The following image shows the Maintenance Free under-sink package. As you can see, the faucet comes pre-lined with tubing and provides a pressure relief function. Only this model is like that. The other 1 stage, 2 stage and 3 stage twist locks faucets do not have pre-lined tubing inside faucet. Therefore, the copper color barrel is bigger and you need to drill a whole of 25mm diameter.

The following image shows the underside of the the measurement of the copper color barrel with diameter less than 25mm.

For further twist lock faucet measurements, please refer to http://www.waterfilter.com.sg/full-package-for-twist-locks-water-filtration . The barrel for Twist locks diameter is 12mm. However, if you use the maintenance Free one (P5250) and then after some time you want to change to the twist locks, you just have to put this plate one on top of counter and one below the counter. (see the following image)