Cable gland is one of the electrical components used as an insulation material attaching and securing the end of the cable on the side of the electrical equipment. This product has extra power to hold the explosion and arcing out of the electrical panel. This type of cable gland cannot stand alone. Some accessories are needed to complete its function.
Cable gland itself has various types in terms of material, as stated by Wikipedia, made of:
Plastic
Brass
Aluminum
Stainless steel