Inductive sensors use a magnetic field to detect objects.  Capacitive sensors use an electric field.  In order to be sensed by an inductive sensor an object must be conductive. This limits suitable targets to metal objects (for the most part). In order to be sensed by a capacitive sensor the target doesn’t need to be conductive. A capacitive sensor will react to an object acting as a dielectric material as well as a conductive object. This makes metal and non-metal objects suitable targets.

A “Peltier” is a solid state Thermoelectric Module.  When powered, it acts like a solid state heat pump (thanks to the Peltier effect) that transfers heat from one side of the device to the other.  Computer enthusiasts sometimes place the wafer like device on top of the processor of their computer with the hot side facing a water block to enhance the cooling of the processor.  Thermoelectric Modules ratings include max temperature difference and max cooling capacity, among others.