fig1 and 2 shows a preferred embodiment of the present invention . it is presented a ring or a band 101 preferably made of metal . the metal ring 101 has a flat , wide edge . the edge has a thickness of such a size that it can hold an id marker . a hole 102 is placed on the edge of the metal ring 101 . the hole 102 is preferably placed at the centre of the width of the ring 101 . the hole 102 can either penetrate the edge of the ring 101 entirely or only partially . the hole 102 is dimensioned in such a way that an id marker can be fitted in it . a preferred way of placing the id marker in the metal ring 101 is to make the hole 102 threaded . this makes it possible to screw the id marker into the metal ring 101 . further it is possible to place the id marker in the metal ring 101 by drilling a hole 102 in the metal ring 101 into which an id marker is placed . further the holes 102 can be closed with e . g . a set screw . the hole 102 is further provided with a small window making it possible to read the id marker . the metal ring 101 is provided with another hole 103 . this hole 103 can be used for placing a galvanic anode . this prevents corrosion of the metal ring 101 and the pipe or tubing . in other embodiments of the present invention the number of holes 102 , 103 can vary either having no second hole 103 , or the metal ring 101 can be fitted with several smaller holes . fig3 shows an embodiment of the invention where the metal ring 101 is mounted to the pipe or tubing 301 . it is shown that the metal ring 101 can be fitted anywhere on the pipe or tubing . the method of connecting the metal ring 101 to the pipe or tubing is to shrink the metal ring 101 so that it fits the pipe or tubing . this can be done either thermally or mechanically . a protective and / or electrically insulating material can be installed between the metal ring 101 and the pipe wall for further protection and / or corrosion inhibition of the pipe . further the id marker can also be fitted in the coupling between two sections of pipes or tubing . this can be done either by adding a section to an existing coupling or , if possible , it can be drilled a holes 102 in the coupling into which the id marker is attached . the way of attaching the id marker to the coupling can be done in the same way as in the embodiment of the metal ring 101 .