Shivaling has three distinct parts which are considered as portions of Brahma, Vishnu and Shiva. The lower part represents Brahma, the middle Vishnu and the upper and the most prominent represents Shiva. Thus, Shivling represents all the three powers in one- as the Param Braham or Supreme Shiva. Another interpretation considers Shivling to be divided in two parts Shiva and Shakti. The top part is considered Shiva and the yoni is considered to be Shakti.
Snakes (Nagas) have been a part of worship in Hinduism from the very beginning. The most famous myth of Lord Shivas association with snakes is when he drinks the poison (kalakuda) from Snake Vasukis mouth during the churning of ocean to get amrit. From that day, Lord Shiva becomes blue throated and is called Nilakantha.
There is mysterious and indescribable power in Shivaling to induce the concentration of mind. It is like the crystal glazing, mind easily attains one-pointedness by looking at the Shivaling. This is the reason why ancient scholars and sages advocated the worship of Shivaling and its installations in temples.
Design: Made in copper.
Copper is well known for its grasping capacity. It grasps the divine spirit (sattvikta) upto 30%, when compared to other metals. Copper can destroy bad spirits like Raj & Tam (i.e. darkness & bad behavior). The spiritual vibrations are attracted towards copper items easily. Just as copper has the ability to absorb the sattvik frequencies of deities, it has also capacity of transmitting them. Thus it becomes rich in divinity in a short period.