diff --git a/include/iso15.h b/include/iso15.h
index 01d62f183..7d2b0e12f 100644
--- a/include/iso15.h
+++ b/include/iso15.h
@@ -39,9 +39,9 @@ typedef enum ISO15_COMMAND {
 } iso15_command_t;
 
 typedef struct {
-    uint8_t flags;      // ISO15_COMMAND
+    uint8_t flags;      // PM3 Flags - see iso15_command_t
     uint16_t rawlen;
-    uint8_t raw[];
+    uint8_t raw[];      // First byte in raw,  raw[0] is ISO15693 protocol flag byte
 } PACKED iso15_raw_cmd_t;
 
 #endif // _ISO15_H_