All Glen Research supports use the standard long chain alkylamino (lcaa) linker but differ in the glass pore size, 500Å, 1000Å or 2000Å. The 500Å support is appropriate for shorter sequences, while the 1000Å supports perform better in the synthesis oflonger (>30-mer) DNA sequences. The 2000Å support is best for very long (>150-mer) oligonucleotides. We have instituted an additional QC test for supports to show the length of oligo that can be prepared before a drop-off in coupling due to steric effects begins to occur. The drop-off point is recorded in the Certificate of Analysis. All Glen Research supports are fully end-capped to ensure that the CPG surface is totally inert, thereby avoiding the introduction of impurity sequences containing deletions at the 3'-terminus.