A resister is a group of flip flops or binary cells which holds the binary information. Since a binary cell stores one bit of information an n bit register has n flip flops and capable of storing any information of n bits a resister may have combinational gates that per from some processing task of certain data. The register has logic gates and flip flops. The flip flops stores the binary information and gates control the transition of information into the register. The simplest possible register is one that consist of only flip flops. The simple 4 bit register is shown in figure which is also known as buffer resister.