A vacuum indicator 12 comprising an indicator-element 20 and a deformable membrane 22, wherein when the membrane 22 is in a first state the indicator element is obscured, and when the membrane is in a second state the extent to which the indicator-element is obscured is reduced. The membrane is configured to transition from the first state to the second state on exposure to a decrease in surrounding pressure. The indicator element may comprise a protuberance 26 and the protuberance may project in a direction substantially perpendicular to the membrane. The membrane may comprise a foam material and the membrane may also comprise a guide-hole 28 to house the protuberance. A vacuum assembly 12 comprising first and second skin layers 14 and 16 defining a cavity 18 wherein vacuum indicator 10 is positioned. First and/or second skin layers may be light-permeable, or may be translucent or may be transparent. The assembly 12 may comprise a channel for evacuating fluid from within the cavity.
