Namo Mantra Mantran is from passage 57 of the Jaap Sahib (Dasam Granth) by Guru Gobind Singh ji.

Listen to the Namo Mantra  along with lyrics and translation.
Namo Mantra Mantran|| Namo Jantra Jantran||
Salutations to Master of Mantras! Salutations to the Supreme Yantra!

Namo Ist Iste|| Namo Tantra Tantran||57||
Salutation to Thee O Highest-Entity! Salutations to You the Supreme Tantra! 57.