The principle behind the humble gear was originally discovered by the Satyrs with their inventions of the windmill and the waterwheel, although it was the Humans who took the principle and followed it to its logical conclusion. Gears made of magically-reinforced wood and metal make up the bulk of Cerenbaun mechanical creations, with most mechanical non-magical energy stored by springs and flywheels.
Cerenbaun society has access to a great many mechanical technologies that are not typically encountered in a fantasy setting. Clocks are perhaps the most obvious of such technology; clock making is a common and well-respected occupation, and even the most impoverished households have access to a clock tower in the middle of the town square, or a cuckoo clock in the kitchen. In a twist, it is non-magical clocks that are considered an expensive luxury, and magical clocks are more common and less expensive. Genuine non-magical pocket watches are considered an extravagant luxury, though cheaper hand-held time-pieces with magical components exist.
Locksmithing is another occupation that has a large presence in Cerenbaun society. Locks in general can be quite complex, and 5-tumbler locks are not unheard of. Like clocks, the cheaper locks are usually magical, though these locks are susceptible to magical spells that might open them. Non-magical locks cannot be dispelled, but they are still susceptible to telekinesis or shaping spells that might damage them. The most expensive kinds of locks are both mechanically complex and have magical enchantments placed on them that make them resilient to damage, so a would-be thief needs to be quite resourceful with many different magical and non-magical lock-picking methods in order to successfully open the lock. Many of these locks also have magical fail-safes and life detection spells on them that will trigger alarms or traps if set off.
Chain-driven gearboxes like those in bicycles are a common component in machinary, though the gearboxes usually have a magical source of power. The "bicycle" design for translating human power into mechanical movement is available, but slow in catching on. Most people who want access to non-magical transportation have stuck by horses and coaches, and those with access to magical transportation wonder why anyone would do so all that exhausting pedaling in order to get from point A to point B.
The spring is further another important mechanical device that Cerenbaun smiths put into their mechanical designs, both magical and non-magical. Their ability to store energy and release them have made them invaluable in many complex devices, with springs being the second most popular method of storing energy; magic being the most popular, and flywheels being the third most popular. Steam power and electricity are unheard of, with magic more convenient and cheaper to harness for the same sorts of tasks.
Jennin may be the god of wizardry, but he is also the god of human technology and innovation. His holy symbol is a single-direction gear (connected to a spiral-spring latch) and even the colleges of mages and wizard guilds prominently display this symbol representing Jennin's influence on their art and science of wizardry.