Declension table of ?dvivastra

Neuter	Singular	Dual	Plural
Nominative	dvivastram	dvivastre	dvivastrāṇi
Vocative	dvivastra	dvivastre	dvivastrāṇi
Accusative	dvivastram	dvivastre	dvivastrāṇi
Instrumental	dvivastreṇa	dvivastrābhyām	dvivastraiḥ
Dative	dvivastrāya	dvivastrābhyām	dvivastrebhyaḥ
Ablative	dvivastrāt	dvivastrābhyām	dvivastrebhyaḥ
Genitive	dvivastrasya	dvivastrayoḥ	dvivastrāṇām
Locative	dvivastre	dvivastrayoḥ	dvivastreṣu

Compound dvivastra -

Adverb -dvivastram -dvivastrāt