This is the Electric brake booster, it is an obsolete Jeep electric brake that was made by Bendix, they are out of production, there are only cores available, and those cores are polished up and sold as new. Even the 'new' master cylinder castings have the internal parts from the used cores.
Cores are taken off a car because they have previously failed, or the car has been scrapped because it was worn out, 'Cores' are often rebuilt with new parts and sold as 'rebuilt'. This unit is obsolete and there are no new parts, only old parts from other cores - 'Used' not 'Rebuilt'. The electric motor, accumulator, and pressure switch are constantly failing on all vehicles with electric type brake boosters, and the owners of vehicles with them have to source and replace one of the three parts about once a year - so they are looking for ways to get rid of it and convert to something else. You are being charge $1,100 for a junkyard product.