back to wall toilet pan
A back to wall pan are usually installed in conjunction with built-in bathroom furniture and a concealed cistern.
A back to wall pan is basically a low level toilet pan with a flat back that enables it to be pushed back flat against the wall or WC unit. A flushpipe runs down from the concealed cistern and fits into the back of the pan with a flushpipe connector. It is also possible to build your own unit to house the cistern which can then be finished with the same tiles or waterproof wall panels as the rest of the bathroom giving a continuous, uncluttered feel to the overall design.
The WC unit, in which the cistern is concealed, hides all of the pipework. Access to the cistern must be maintained, so most concealed WC units have a removable front panel and an access hatch in the countertop above the cistern - make sure you allow for this fact if you intend making your own unit. Some concealed cisterns are small enough for access to be gained from the front alone but most will require access from above.
Prior to recent changes in water regulations extended cistern levers had to be used to operate the flush but now many concealed cisterns come with push button flushes which are neater and easier to operate. Many are pneumatically operated allowing the button to be sited remotely from the cistern.