Samar RT36 Toroidal Transformer
Handmade in the US by Samar Audio, the RT36 is a 1:36 step-up transformer for passive ribbon microphones. Made for the Nady RSM4, Stellar RM3, Cascade Fathead, and other Chinese microphones with similar motors (including all the R-121 and Fathead lookalikes).
This is a toroidal design, not a bobbin wound transformer. Toroidal transformers are used in the best ribbon mics in the world.