It is a wooden trunk or chest (50 x 83 x 41’5 cm.), the oldest preserved by the Matriz Brotherhood, which were used to transport the belongings of the sacred image of the Virgin of El Rocío. It is made of 3 cm thick plank. The lid, slightly larger, measures 43 cm. wide by 92.5 centimeters long. It has its mobile supports to be placed high and not directly on the ground, being separated from it 18 cm. On the cover, engraved with iron letters on fire appears the inscription “PROPIA DE LA HERMANDAD DEL ROCÍO/ ALMONTE 1861“.

This chest, which shows all tongue and groove sides, has two iron brackets at each angle, thus showing a total of eight. On each smaller side there is an iron handle to hold it, and on the front there are three locks, the central one being the largest of them all, and today split. The name of this type of ark comes from the latter, since it used to be called “ark of the three keys“.