This spacer is for the top of the synthesis rotor used in the Dr. Oligo 48 and the Biolytic 3900.
It can also be used on the ABI 3900, the MerMade 48 and the Northwest instrument if these instruments have been upgraded to the Biolytic Solid Rotor.

The advantages of this spacer are:
1) Reduces the chamber volume which reduces the gas consumption
2) The spacer design has a mechanism that keeps the synthesis columns from popping up during synthesis.