Several owners report consistently of unraveling seams on the Nightflight key case, partly already after a few weeks' carrying in the trouser pocket. Montblanc exchanges the case under warranty; the problem, however, recurs on replacement deliveries. Precondition for the free exchange is a correctly completed warranty card with purchase date, dealer stamp and concrete article — a foreign warranty card does not help. Larger pieces of the collection (e.g. the Nightflight backpack) are reinforced with leather piping at the outer seams and show hardly any wear. Materially the combination of silk-cotton fabric and rough denim in the trouser pocket is little durable.