Specifications: Air flow tuning via an AFCS Ring adjusting from zero to either D=3.8MM (stock Pos Tube) or D=2.0MM (spare Pos. Tube). Fine tuning with accessory MTL pins kit D=1.0/1.2/1.5MM M2.5MM pan head phillips post screws 12.2MM post-to-post length, ~8.5MM post-to-post net space , ~8.0MM coil space. Max. net coiling height in the chamber 4.2MM Chimney top inner D ~4.0MM