The bluefire M68 spacer set is a great addition to any astronomers accessory list.  You can build, add, and configure them in many arrangements to create that perfect length adapter.  No need to get custom made adapters, simply combined these into your necessary configuration or take apart and reconfigure as needed.  M68 x 1 thread pitch makes them work great with a BlueFire M68 rotator system.  We use these on our RASA 11 PRO ASG Photon Cage system.  They mount perfect to our RASA 11 M68 camera mount and then into a rotator or our M68 filter slider system.

Special Note: Due to manufacturing tolerance variations, this item is NOT recommended for use with ZWO's M68-OAG (these spacers may not thread in smoothly or fully into ZWO's M68 thread). They will work well with other M68x1 threads on products from Baader Planetarium, Blue Fireball, Sharpstar, QHY, etc.

• • Set of eight M68x1 threaded spacer rings
  • Precision CNC-machined, black anodized aluminum
  • Each spacer features an M68x1 male thread on one side and an M68x1 female thread on the other side
  • Included spacer lengths: 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm and 20mm
  • Male M68 thread length is 3mm on all spacers
  • Female M54 thread length varies from 4.1mm (for the 5mm spacer) to 10.1mm (for the 20mm spacer) 
  • Maximum outside diameter = 74mm (2.91")
  • Total weight of all 8 spacer rings = 5.7oz (161g)