Abstract: Method for attaching a sample vessel rack (1, 1?) in an apparatus (2, 2?, 23), which apparatus comprises a slot (4, 24) into which the sample vessel rack is inserted, wherein magnetic attraction force is utilized in the attachment and correct positioning of the sample vessel rack (1, 1?) into the slot (4, 24), where in the slot (4, 24) comprises a movable member (9, 9?, 28, 35), which movable member is moved to a locking position with a magnetic attraction force when the sample vessel rack (1, 1?) is in a correct position in the slot, and which movable member comprises at least one protrusion (11, 33) which protrusion sets itself in a notch (37) formed in the sample vessel rack in the locking position of the movable member. The invention also relates to such a sample vessel rack and an apparatus, and to a use of such a sample vessel rack.