Declension table of ?vivastra

Masculine	Singular	Dual	Plural
Nominative	vivastraḥ	vivastrau	vivastrāḥ
Vocative	vivastra	vivastrau	vivastrāḥ
Accusative	vivastram	vivastrau	vivastrān
Instrumental	vivastreṇa	vivastrābhyām	vivastraiḥ vivastrebhiḥ
Dative	vivastrāya	vivastrābhyām	vivastrebhyaḥ
Ablative	vivastrāt	vivastrābhyām	vivastrebhyaḥ
Genitive	vivastrasya	vivastrayoḥ	vivastrāṇām
Locative	vivastre	vivastrayoḥ	vivastreṣu

Compound vivastra -

Adverb -vivastram -vivastrāt