The Linear Ball-Bearing Pivot Unit is an optional upgrade for the first revision of Hapstone M2 utilizing PTFE insert. The linear ball-bearing provides extra smooth shaft movement and requires no lubrication or cleaning.
One of the best selling points of flagship Hapstone R1 comes to Hapstone M2. The second revision of Hapstone M2 implements the linear ball-bearing pivot unit. Owners of Revision 1 can purchase the linear ball-bearing pivot unit separately.
Quotes
The linear bearing equipped instrument, is by far the smoothest, and virtually play-free, guided rod system I've used thus far. There is no vibration, or perceivable movement, but its able to simultaneously exhibit extremely precise and smooth reciprocating, linear action.
Daniel Gigli, Quality Technician/Engineer