Key to Vector Sigma

The KtVS is an object in the Generation 1 continuity family.

The Key to Vector Sigma was an ancient device that was connected to Vector Sigma and allowed a Transformer to activate the ancient intelligence. It appeared as a small remote with an overdeveloped power circuit and had the ability to control the robotic guardians that remained in the lower levels of Cybertron that guarded Vector Sigma.

Fiction

Generation 1 cartoon

By the 20th century, the Key was present in the hands of Alpha Trion on Cybertron until his home was attacked by the Decepticons who gave the key to Megatron in his quest to imbue five cars with intelligence. Megatron would face some resistance from the guardians below but learnt that the Key could reprogram them. He would activate Vector Sigma and give life to the Stunticons. The Key to Vector Sigma, Part 1

When he returned to Earth, Shockwave informed him that the Key possessed a different power on Earth which was capable of destroying it. Megatron accidently learnt, while studying the Key, that it was capable of transforming matter into metal. He began the process of transforming Earth into another Cybertron but was defeated by the Autobots. Silverbolt would later destroy the Kety after he forced Megatron to drop it which reversed its effect on Earth. The Key to Vector Sigma, Part 2

Beast Machines cartoon

There were lots of 'em.

From Teletraan I: The Transformers Wiki, a Wikia wiki.