water permeable in the direction of the storage layer and water impermeable in the direction away from the storage layer the blocking layer is arranged so as to face the outer side and is water impermeable in the direction away from the storage layer and the blocking layer forms an intermediate space for storing condensed water which is formed from the steam transferred into the storage layer through the transfer layer application_number US 201515120227 A description basically in the figures the same parts are provided with the same reference numerals the covering envelope 1 1 1 2 1 3 according to fig1 a to 1 c includes a multi layered construction the covering envelope 1 1 1 2 1 3 forms a body side 3 that faces the body of a person 4 which is to be kept warm as well as an outer side 2 that is arranged opposed to the body side 3 and in particular faces the environment the covering envelope 1 1 1 2 1 3 in each case has a transfer layer 6 1 6 2 6 3 which faces the body side 3 a blocking layer 11 1 11 2 11 3 which faces the outer side 2 as.