Toa canisters were transport vehicles built by Matoran in [Karda Nui] and placed in various spots throughout the universe. The canisters were said to be safe for use only by Toa, although others used them and survived. They were capable of moving at high speed, could pass through solid rock, and appeared to be able to hone in on a location based on the traveler's thoughts.
When surveying Mata Nui from above the Kini-Nui, Zaktan spotted six large Toa canisters resting on their ends in a row near the base of the mountain. They had obviously been placed there for a reason. Their condition showed that someone had been tasked with taking care of them.
Toa canisters were one-person transport units. They could move through solid rock as if it were water. They responded to the rider's thoughts. They were not built for a safe and comfortable ride. Common wisdom was that no one with less than the power of a Toa could survive their use.
Canisters could not be piloted; they tended to drive themselves.
Toa canisters were used for transport within the Matoran Universe.
Some Toa canisters came ready with weapons inside.
Canisters were quite durable, as evidenced by the fact that the Toa Mata's canisters survived in the ocean for 1000 years.
Canisters were not made only for the Toa Mata, but for any and all Toa who needed to use them.
Toa canisters could move through solid rock as well as travel underwater.
Some canisters were built by Matoran of Light, some weren't. They were built in many different places.