This is a larger 9.5mm (3/8" inch) diameter tubing.
 
This line is made from PE (polyethylene) which is not only BPA and plasticiser free but it's also NSF approved.
 
Suitable for pressures up to 150psi/10.3bar/1000kPa this will handle mains water pressure no problem at all.
 
This type of line is often used on water dispensing systems that require less resistance than the smaller 1/4" hosing.