Declension table of ?vajraka

Neuter	Singular	Dual	Plural
Nominative	vajrakam	vajrake	vajrakāṇi
Vocative	vajraka	vajrake	vajrakāṇi
Accusative	vajrakam	vajrake	vajrakāṇi
Instrumental	vajrakeṇa	vajrakābhyām	vajrakaiḥ
Dative	vajrakāya	vajrakābhyām	vajrakebhyaḥ
Ablative	vajrakāt	vajrakābhyām	vajrakebhyaḥ
Genitive	vajrakasya	vajrakayoḥ	vajrakāṇām
Locative	vajrake	vajrakayoḥ	vajrakeṣu

Compound vajraka -

Adverb -vajrakam -vajrakāt