While the nearby Wn83 Maisy Batterie was based around open emplacements for 155mm cannons, the Wn83 Maisy Batterie Brasilia La Martinere opted to place their big guns inside four casemates.
Three R612 type casemates were built at the location to the east of the Maisy Batterie, with a fourth still under construction when the Allies landed on the nearby Omaha and Utah beaches. Each casemate housed a Czech-built Skoda 10cm howitzer inside.

The eastern R612 casemate stands on agricultural land with the two other casemates fenced off and largely overgrown so cannot be accessed.
The site also features a R607 twin-room ammunition bunker and a R622 double group personnel shelter behind the casemates. Excavation of the site for a TV series presented by explorer/adventurer Josh Gates a few years back saw the opening up of the R622 and R607 but the entrances to these have now been partially refilled and have become overgrown.

A ring of Tobruks surround the casemates and the remains of ammunition storage niches can be found to the rear of the casemates next to the road through the site.

Wn84 is on situated on private farmland and some areas are dangerous to visit and so this site isn't accessible to the public.