You are looking for a plastic tube about 3cm in length.
This cache is not at the posted coordinates.
The clues to work out the coordinates for this cache are provided on completion of the five stages of the 'Robert Thomas, the sculptor' Ad Lab cache.
The cache is hidden at:
N51 AB.CDE W3 FG.HJK
Oenpxrg ba oynpx qenva cvcr haqre frphevgl pnzren.