diff --git a/eic_data.yaml b/eic_data.yaml
index ca4b5ed73efa3a557d6fdf6c6d09760710f53496..e6f625575e1ab4b89e177e0fd319bce85d4b0e48 100644
--- a/eic_data.yaml
+++ b/eic_data.yaml
@@ -224,6 +224,7 @@ components:
       - float             npe               // Overall p.e. count associated with this estimate
       - float             theta             // Cherenkov theta angle
       - float             rindex            // Average refractive index for this collection of photons
+      - float             wavelength        // Average wavelength for this collection of photons
 
 datatypes: