The R2B Shchit, also referred to as Defense ACs, are a line of powerful, mass-produced units capable of being a very potent deterrent against mercenary ACs. Although not as powerful as fully-customisable mercenary Armored Cores, the R2B line is often used as a force multiplier in situations where such ACs are too costly to hire or use in the field. They appear in Armored Core V and later as a renamed, redeveloped variant in Armored Core: Verdict Day.