Male is Unique ID 50 in the IAB Audience Taxonomy 1.1, in the Demographic branch under Demographic → Gender. Trillboards emits it on the bid request as a segtax=4 segment, the code every IAB-compliant DSP already reads, so a buyer already running "Male" elsewhere can point that strategy at DOOH screens without rewriting taxonomy. Over the most recent 30-day window the network logged 67,611 cohort observations tagged with this segment across 26,269 approved screens.
Trillboards inventory concentrates in Taxi Rideshare Tv, Convenience Store, Grocery. Taxi Rideshare Tv is the largest category at 11,684 approved screens, average floor $2.40 CPM. Those are network-wide venue counts; add a venue filter to the line item to hold delivery to the surfaces you want.
Buying one or two tiers up captures more of the network and less of the segment; buying this leaf does the reverse. The OpenRTB payload carries every level of the chain, so a single bid request can be targeted at Male or at any node above it. Demographic cohorts sit well under a frequency cap and a brand-safety overlay, especially when you stack adjacent segments.