- Material - Glass-fibre reinforced polyamide based technopolymer (PA) with the exception of VB.639/130 which is in glass-fibre reinforced polypropylene based (PP) technopolymer. The VB.639 Three-Arm Knob is resistant to solvents, oils, greases and other chemical agents.
- Colour - Black, matte finish.
- Execution A: black-oxide steel boss, plain blind hole.
- Execution B: brass boss, tapped blind hole.