The Beacon is compatible with most dynamo taillights, with the requirement that they do not ground to the bicycle frame.
The Beacon IS compatible with the Supernova E3 Taillight, although an extra 60Ω resistor must be wired in series between the Beacon and the E3. We have that resistor available here:
Compatible taillights include:
Many other taillights are compatible and this list will expand as more are tested. Please contact us if you have any questions about a particular taillight.