This guy serves up the original Muff Pi from 1969: thick and meaty. It's a Yi from me.

Model: Electro-Harmonix Triangle Big Muff Pi Fuzz Pedal 
Made: USA, 2021
Serial: 202110075445
Type: fuzz
Power: standard 9v DC negative power supply (not included)
Equivalent New Street Price (Approx): N/A
Mods: none
Accessories: none

Condition Notes: used, no major marks. Tested and fully functional.
Overall: excellent condition (9/10)