diff --git a/g203-led.py b/g203-led.py
index a8b4f7d..c6bdec4 100755
--- a/g203-led.py
+++ b/g203-led.py
@@ -9,6 +9,7 @@ import sys
 import usb.core
 import usb.util
 import re
+import binascii
 
 g203_vendor_id =  0x046d
 g203_product_id = 0xc084
@@ -18,7 +19,7 @@ default_brightness = 100
 
 
 dev = None
-intf = None
+wIndex = None
 
 
 def help():
@@ -101,37 +102,37 @@ def set_led_cycle(rate, brightness):
 
 def set_led(mode, data):
     global dev
+    global wIndex
 
     prefix = '11ff0e3b00'
     suffix = '000000000000'
     data = prefix + mode + data + suffix
-    data = [ int(''.join([data[i], data[i+1]]), base=16) for i in range(0, len(data), 2)]
 
     attach_mouse()
-    dev.ctrl_transfer(0x21, 0x09, 0x0211, 0x01, data)
+    dev.ctrl_transfer(0x21, 0x09, 0x0211, wIndex, binascii.unhexlify(data))
     detach_mouse()
 
 
 def attach_mouse():
     global dev
-    global intf
+    global wIndex
     dev = usb.core.find(idVendor=g203_vendor_id, idProduct=g203_product_id)
     if dev is None:
         print_error('Device {:04x}:{:04x} not found.'.format(g203_vendor_id, g203_product_id))
-    intf = 1
-    if dev.is_kernel_driver_active(intf) is True:
-        dev.detach_kernel_driver(intf)
-        usb.util.claim_interface(dev, intf)
+    wIndex = 0x01
+    if dev.is_kernel_driver_active(wIndex) is True:
+        dev.detach_kernel_driver(wIndex)
+        usb.util.claim_interface(dev, wIndex)
 
 
 def detach_mouse():
     global dev
-    global intf
-    if intf is not None:
-        usb.util.release_interface(dev, intf)
-        dev.attach_kernel_driver(intf)
+    global wIndex
+    if wIndex is not None:
+        usb.util.release_interface(dev, wIndex)
+        dev.attach_kernel_driver(wIndex)
         dev = None
-        intf = None
+        wIndex = None
 
 
 if __name__ == '__main__':