54mm Extended Bulkhead
Smoke well is 1.875" deep by 1.25" wide smoke well (behind snap ring) with 1/4-20 thread attachment point on top.
Is capable of "experimental" (but proven) head-end ignition with a modified smoke grain.
The liner shoulder incorporates a liner sealing o-ring acting the same as a seal disk found in other brands. This is designed for use strictly with convolute phenolic liners. Spiral wound liners must not use this o-ring.
The external threads are in place for future accesories that may be developed.