I believe the accepted terms for UDS sizes are
55 gallon drum "UDS" uses parts from 22.5" kettle
30 gallon drum "midi UDS" uses parts from a 18.5" kettle
15/16 gallon drum "mini UDS" uses parts from a smokey joe sized kettle.
And a PBC is a 30 gallon drum with fancy rods and hooks. <<this one requires the use of lighter fluid per instructions.
Modded Brinkmann Gourmet. Basic UDS. Rescued 22.5" OTS. SJS Mini-WSM. Stubbs. B&B Oak Lump.
Cannondale 2009 F8 (for burning off all the great BBQ)