Insulations can refer to materials used to reduce the rate of heat transfer or flow of electric current.
RH Nuttall Limited offers washers, gaskets, strips and sheet in the form of insulations in two different types:

Electrical

Electrical or dielectric insulations are usually manufactured from a material that restricts the flow of electric current. They intend to support or separate the electrical conductors without passing a current through themselves. Materials such as Presspahn, Silicone, PTFE, some foam based products, or Nomex gaskets can be used to guard electrical contacts / conductors in circuit boards from coming into contact with tools or fingers. Creases and perforations can also be added to facilitate folding into a three dimensional shape.

Thermal

Thermal insulators refer to materials used to reduce the rate of heat transfer. Refractory ceramic fibre board is commonly used to insulate gas fire backs; the parts can even be dust suppressed with a spray on sealant.

Presspahn Insulation

Ceramic paper or mineral papers are both versatile materials that can be used for insulations or gaskets in a variety of applications.

Glass needlemat or ceramic blanket may be wrapped around a number of components of a product to protect it from excessive heat transfer. For example, around the inner cooking area of a domestic oven. The material can be aluminium foil coated or fully encapsulated to aid even further in the thermal insulation process.