Every IDT custom oligo is synthesized to order through a series of tightly controlled steps, including the coupling of the individual bases, cleaving the oligo from the solid support, desalting, and if requested, purification. Each of these steps will result in a loss of final yield, which varies with each synthesis. Due to this variation, IDT oligos are ordered according to the amount of starting material, also referred to as the scale. All custom oligos are assigned a minimum yield guarantee, but lot-to-lot variability in the final delivered quantity should be expected, even when reordering the same sequence. For further questions about this subject, please contact email@example.com.