Three Deities of the Great Master Vajrapani (Wyl. mkhan chen phyag rdor ba'i lha gsum) —
These three deities of protection are referred to in the prayer Homage to the Buddhas and Bodhisattvas by Kyabje Trulshik Rinpoche.
The empowerment of Nyenpo Lhasum is an empowerment of these three deities in one.
RigpaWiki:Three Deities of the Great Master Vajrapani