diff --git a/compose.yaml b/compose.yaml
index 43e1ba3b..2dd4b8db 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -71,6 +71,8 @@ services:
       - PATH_TO_CLIENT_CERT
       - PATH_TO_VERIFY_CERT
       - POSTGRES_PASSWORD
+      - PRESELECTOR_CLASS
+      - PRESELECTOR_MODULE
       - SCOS_SENSOR_GIT_TAG
       - SECRET_KEY
       - SIGAN_MODULE
diff --git a/env.template b/env.template
index 592edd9c..ed42266e 100644
--- a/env.template
+++ b/env.template
@@ -79,6 +79,8 @@ SIGAN_MODULE=scos_tekrsa.hardware.tekrsa_sigan
 USB_DEVICE=Tektronix
 DEVICE_MODEL=RSA507A
 BASE_IMAGE=ghcr.io/ntia/scos-tekrsa/tekrsa_usb:latest
+PRESELECTOR_MODULE="its_preselector.web_relay_preselector"
+PRESELECTOR_CLASS="WebRelayPreselector"
 
 # SECURITY WARNING: You should be using certs from a trusted authority.
 #                   If you don't have any, try letsencrypt or a similar service.
diff --git a/src/initialization/__init__.py b/src/initialization/__init__.py
index 82822e38..53149c89 100644
--- a/src/initialization/__init__.py
+++ b/src/initialization/__init__.py
@@ -54,7 +54,7 @@ def load_preselector(
     logger.debug(
         f"loading {preselector_class_name} from {module} with config: {preselector_config}"
     )
-    if module is not None and preselector_class_name is not None:
+    if module and preselector_class_name:
         preselector_module = importlib.import_module(module)
         preselector_constructor = getattr(preselector_module, preselector_class_name)
         preselector_config = load_from_json(preselector_config)