This is the unique 8 points locking system designed at BMS for stopping the base ferrule on their flag pins from rotating. Most ferrules have only two or four locking points which can quickly wear under prolonged use, with 8 points of contact the extra durability is self explanatory.
These ABS plastic hole cups are made from the best quality composite money can buy. Includes special additivies to give a brilliant white glow to the inside on the cup whilst the base is black hiding dirt and general wear and tear over time along with making the ball more visible.
20mm dia hole for UK ferrules.