WL9-2811 PP Precision Instrument Case

The outer shell is 280 x 225 x 111 mm and the internal cavity is 253 x 180 x 98 mm. Externally the case occupies 280 x 225 mm while the usable floor inside is 253 x 180 mm, the difference coming from the wall section, the seal channel and the moulded closing geometry rather than measurement error. Size a load from the inner dimensions, never from the outside, because outside figures overstate capacity. With 98 mm of inner height over a 253 x 180 mm floor, the body is deeper than its footprint suggests, so small upright meters and long slim fixtures both fit.

The lid adds 27 mm of internal depth and the base adds 71 mm, giving 98 mm of combined inner height. A 27 mm lid over a 71 mm base keeps the mass low, so upright contents hold their centre of gravity in the body and are less likely to topple when the case is carried; conversely, parts with raised fittings on top will be pressed by the shallow lid.When judging whether a body suits your contents, read the base figure first, because it sets how tall an item can stand, while the lid figure decides how much headroom remains above it. Only the sum of the two is usable height, and when measuring a part, include handles, connectors and bosses, or the lid will press on it once closed.

The shell uses a sealed closure and provides an IP67 waterproof and dustproof rating. For instrument transport the closure keeps out both dust and moisture, which limits contamination of connectors and optical surfaces. The rating applies to the sealed cavity of the case itself, so if you store moisture-sensitive contents, pair it with desiccant or a humidity management accessory and check the sealing face for trapped debris every time you close the lid, since a single trapped fragment undermines the seal.

The factory usage categories listed for WL9-2811 are precision instrument cases and hardware tool cases. With a 253 x 180 x 98 mm cavity, a 5 mm wall and an 890 g unit weight, it suits handheld meters, sensor assemblies, small inspection fixtures and matching hand tools as fixed-station storage or a vehicle-transport case. Contents taller than 98 mm should move to WL9-2817, which shares the footprint, rather than being laid in at an angle.

Both models share the same footprint, wall and lid: 280 x 225 mm outside, a 5 mm wall and a 27 mm lid depth on each. The only difference is base depth. WL9-2811 has a 71 mm base, 98 mm of combined inner height and an 890 g unit weight, while WL9-2817 has a 125 mm base, 152 mm of inner height and a 940 g weight. Choose purely on content height: up to 98 mm take WL9-2811, anything taller take WL9-2817. Because the footprint is identical the two models share one pallet and carton layout, so a mixed order does not need two packaging designs.