The present invention relates to a reservoir (10; 30; 40) for a liquid medicament (11), comprising: a first boundary portion (16; 36; 46) and a second boundary portion (18; 38; 48) forming a cavity (12; 32; 42) to receive the medicament, wherein the first boundary portion is sub-stantially opaque and flexible, and wherein the second boundary portion is substantially transparent and rigid.