The Olympus Stylus-550WP - badged mju 550WP outside North America - is a waterproof compact introduced in January 2009. It sat below the fully ruggedised Tough models as a slim, water-ready snapshot camera rather than a drop-proof one.
It is waterproof to 3 metres but, unlike the Tough series, carries no shockproof or freezeproof rating, and pairs a 10MP CCD with an internal 3x zoom of 38-114mm equivalent, digital image stabilisation, a 2.5-inch LCD and standard-definition video. Storage is the awkward part: it takes xD-Picture Cards, with microSD supported only via Olympus's MASD-1 adapter.
Its place in the catalogue is as the cheap-and-cheerful end of the waterproof niche - a camera bought for one beach holiday and drawered ever since, which is why UK listings are so plentiful. The 38mm-equivalent wide end is restrictive by modern standards, but as a splash-safe pool camera for a few pounds it still does the job it was built for.
Buying checks are two-pronged: seals and storage. Open the single sealed door and inspect the gasket for perishing and the compartment for corrosion or salt residue, remembering the 3-metre rating leaves little margin on ten-year-old rubber; then confirm what card it comes with, because xD cards are discontinued and dearer than the camera, so an included xD card or MASD-1 microSD adapter materially changes the value. Also test the internal zoom and screen for fogging behind the front window, and check the LI-42B battery still takes a charge.