diff --git a/eic_data.yaml b/eic_data.yaml
index 52e83410d685e3900f37e36715f8b8d509711d24..7190c3840bffd5ec916cb13c45db1d3c505e565f 100644
--- a/eic_data.yaml
+++ b/eic_data.yaml
@@ -269,6 +269,7 @@ 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: