diff --git a/tangostationcontrol/tangostationcontrol/devices/recv.py b/tangostationcontrol/tangostationcontrol/devices/recv.py
index 5070b8cef0f54e5d4165701ccaefe0a637faf2d7..e6f0d1f36ed16790f5532b7f9cafce3419ff8579 100644
--- a/tangostationcontrol/tangostationcontrol/devices/recv.py
+++ b/tangostationcontrol/tangostationcontrol/devices/recv.py
@@ -61,6 +61,9 @@ class RECV(opcua_device):
     RCU_LED_colour_R = attribute(dtype=(numpy.uint32,), max_dim_x=32, fget=lambda self: (2 * self.proxy.RCU_LED_green_on_R + 4 * self.proxy.RCU_LED_red_on_R).astype(numpy.uint32))
 
     ANT_mask_RW                  = attribute_wrapper(comms_annotation=["ANT_mask_RW"               ],datatype=numpy.bool_  , dims=(3,32), access=AttrWriteType.READ_WRITE)
+
+    # The HBAT beamformer delays represent 32 delays for each of the 96 inputs.
+    # The 32 delays deconstruct as delays[polarisation][dipole], and each delay is the number of 'delay steps' to apply (0.5ns for HBAT1).
     HBAT_BF_delays_R             = attribute_wrapper(comms_annotation=["HBAT_BF_delays_R"          ],datatype=numpy.int64  , dims=(32,96))
     HBAT_BF_delays_RW            = attribute_wrapper(comms_annotation=["HBAT_BF_delays_RW"         ],datatype=numpy.int64  , dims=(32,96), access=AttrWriteType.READ_WRITE)
     HBAT_LED_on_R                = attribute_wrapper(comms_annotation=["HBAT_LED_on_R"             ],datatype=numpy.bool_  , dims=(32,96))