What does SHANKA & CHAKRA represent?

The Sankha and Chakra, the religious symbols of the Sri Vaishnavites, are the sacred weapons of Lord Vishnu.

About Sankha:

The Sankha or the Conch has the form of a multiple spiral evolving from one point into ever increasing spheres. This symbolises the origin of the Universe from a single source, viz., the God. Being found in water, it represents the causal water from which the universe was evolved and into which it gets dissolved. When blown, it produces a sound which represents the primeval sound, pranavam, from which creation developed. It is also taken to be the representation of the cosmic Ego.

About Chakram:

The chakra or discus represents the Universal Mind., the unlimited power that creates and destroys all the spheres and forms of the Universe, the nature of which is to revolve or to change. It also represents the Lord’s will to multiply. Its six spokes denote the six seasons of the year, hence the changing Universe set on the unchanging axle. The pivot, represents the magic syllable Hrim of the Lord. The circle round the wheel is alankara, the divine power of ego. On the microcosmic plane, it can be taken to be a true representation of the individual’s mind, which is ever changing like the rotating wheel.

The symbols of the Conch and discus, which are imprinted by Acharya on the shoulders of disciples, are believed to dispel darkness in men and women. People get initiated with the insignia of the conch and the discus. These are like passports for entry to Sri Vaikuntam.

Our good or bad deeds are recorded on the body (Chitra Gupta does not have the wherewithal for recording the sins and virtues of all the people; that is why they are registered on the body). The past sins of a person cannot be wiped out and they remain like roasted seeds which cannot germinate. Since the hands do the various types of deeds, the symbols are cast on the shoulders, so that they will check the tendency to indulge in misdeeds. They also purify the body (Thapasamskara) and when the mortal coils are shed, these symbols act as entry passes for the souls to reach Sri Vaikuntham.