Complete Diaphragm, Seat and Seat Cap assembly.Unlike some other cheaper regulators these seat and seat cap assemblies come as a completely encapsulated (enclosed unit).  On the base of the seat and seat cap assembly you can see we use an additional sintered filter.  This reduces the chance of contamination and reduces the chance of pressure creep.  The fully encapsulated seat design also means that if the regulator is serviced in an environment that is not completely clean you have less chance of getting contamination into this sealed assembly