The double check valve for the push-fit connection of plastic and copper pipe. Designed, manufactured and assembled in the UK by John Guest Speedfit.
 
 
 
The double check valve only allows water to flow through in one direction, therefore, preventing backflow of potential contaminants.
 
 
 
To install, simply push the valve fully on to the pipe. Should the need arise to demount the connection push the collet towards the body of the fitting and pull the pipe to release. Installation can be reduced by around 40% against traditional fixing methods.