M4 Octabolt housing compatible with the OpenBCI Ultracortex system. This is only the bolt, and does not include the electrode, holder, and connecting wire. This version is available in long (large) and short (small) variants to help extend the fit range of the headset, as well as in different colors. The complete Ultracortex electrode kit ("Print-it-yourself" kit) is available in the OpenBCI shop
here.