diff --git a/dev-hardware-quality-control.md b/dev-hardware-quality-control.md
index cec12d5c..e8089a3e 100644
--- a/dev-hardware-quality-control.md
+++ b/dev-hardware-quality-control.md
@@ -24,7 +24,7 @@ PC has USB CDC with Stim.
 
 PC _probably_ has USB CDC with ECU. Funny idea: CAN bus between ECU and Stim?
 
-Problem: sometimes we do not want to feed ECU via ST-Link. Solution: Stim has a switch(es) to break +5v line(s) between PC and ECU.
+Problem: sometimes we do not want to feed ECU via ST-Link. Solution: Stim has a switch(es) (red board on the photo) to break +5v line(s) between PC and ECU.
 
 
 ![x](Hardware/hw-qc-overview.jpg)