  For a perfectoid ring $R$ and a natural number $n$ we investigate the
essential image of the category of truncated by $n$ Barsotti-Tate groups under
the anti-equivalence between commutative, finite, locally free, $R$-group
schemes of $p$-power order and torsion Breuil-Kisin-Fargues modules over $R$.
We describe the associated semi-liner algebra data and show as a consequence
that every $\text{BT}_n$-group over $R$ is the $p^n$-torsion of some
$\text{BT}$-group.
