Aprox 12.5 (.492) diameter by .230 (5.7mm) tall it has 3 flat bands slightly rounded on the bottom no relief cut on the bottom.
Apx .250 (6.2mm) tall and 1/2 (13mm) dia. it has 3 rounded beads the relief cut on the bottom fits aapx 11mm/7/16 lower body.
Aprox .500 (1/2 or 13mm) this makes the basic custom Sierra style center band piece. It can be threaded 8.4mm x 1 for the standard trans mission or have a 8mm tube soldered in and trimmed to fit. the lower end fits into an 8mm standard tube using one of our 8mm nibs. The tube length is adjusted according to your design and length of the transmission tube. the upper end fits into the standard Sierra style 10,5mm body tube.