The next level in thermostats, these are a slightly more complex version of thermostat. These shouldn't be used with light-emitting bulbs, but are capable of controlling temperatures to what you set, and also come in a high-range option, to provide for higher temperature levels.
Pulse Thermostats are for non-light-emitting heat sources only, such as heat cable, mats and ceramic emitters. They pulse with greater or less intensity depending on whether the temperature needs raising or lowering - an action that is not compatible with glass bulbs, but works great otherwise.