# Are custom primers loaded as a pool or individually on the iSeq 100?

For the iSeq 100, custom primers are loaded individually for each read. For more information, see the [iSeq 100 Sequencing System Guide](https://support.illumina.com/downloads/iseq-100-system-guide.html), and search Knowledge Base article **Spiking custom primers into the Illumina sequencing primers**.

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #6504), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000006504%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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