Insulated flat receptacles are electrical contact elements which are made of sheet metal and are designed with or without a support sleeve in the crimping area. Their dimensions are designed in accordance with DIN, or deviated from accordingly. Flat receptacles are available in a wide variety of plug sizes, materials and surfaces and usually have a crimping area for the cable connection. The variant with support sleeve usually achieves a higher pull-out force of the strand from the crimping area than the variant without support sleeve.