Airtight enclosure

An airtight enclosure comprising a pair of enclosure shells, each enclosure shell having:

• a pair of first edges, each first edge having a first length and extending in a first direction and
• a pair of second edges, each second edge having a second length shorter than the first length and extending in a second direction transverse to the first direction,
• wherein
• the pair of first edges are spaced apart by a distance corresponding to the second length,
• the pair of second edges are spaced part by a distance corresponding to the first length,
• and wherein
• the pairs of first edges have complementary assemblages comprising a tongue and a groove, respectively, with mating geometries for assembling first edges of respective ones of the enclosure shells in sealing contact, and
• at least one second edge of the pair of second edges has a groove for accommodating a resilient sealing member in sealing contact with a second edge of the other one of the pair of enclosure shells so that mating edges of each pair of second edge portions allow being assembled within a range of relative positions transverse to their longitudinal direction with the resilient seal or gasket in sealing contact with the mating edges.