> For the complete documentation index, see [llms.txt](https://emotiv.gitbook.io/epoc-user-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://emotiv.gitbook.io/epoc-user-manual/troubleshooting/electrode_arms.md).

# Electrode Arms - Alternative References

The following images display the arms of the headset to allow you to identify each sensor for troubleshooting.

## Left

![](https://lh6.googleusercontent.com/Ui9YL-HvHFKIFkipeLQCQ8dfNjcho4eKM9TEUWSE5RhqdOphQNn-39qLJvCrCjQ21jrZ5iwbnzYAsRXSqkPmWlKsqPkc8B4jYYxpIvxptGg_ZuatWPwTDuMnW47Ftlw-waLsPKpy)

## Right

![](https://lh4.googleusercontent.com/LgH86uuRlBqXvtGWhXaWafOlHC7tr_CRy-r1ay2_oiIEhoDLR7_IPYzP3jr2N-uaJ5-m-mrdndlo5QIYxVHR8LXrj-dGDrCStGHnEHRVEcvU4C7ImHMAo816yGdoyqQO_BkM-BP9)

The DRL(P4) / Aux DRL (M1) and CMS (P3) / Aux CMS (M2) channels are wired together to allow the user to change the location of the references. If you are having problems getting good contact quality due to thick hair, please try the second position.