diff --git a/usb/util.js b/usb/util.js
index 2c102dad..da56a0e9 100755
--- a/usb/util.js
+++ b/usb/util.js
@@ -1,14 +1,14 @@
-var usb = require('usb');
+let usb = require('usb');
 
 exports = module.exports = {
-    getUsbEndpoints: function() {
-        var vid = 0x16d3;
-        var pid = 0x05ea;
+    getUsbEndpoints: () => {
+        let vid = 0x16d3;
+        let pid = 0x05ea;
 
-        var device = usb.findByIds(vid, pid);
+        let device = usb.findByIds(vid, pid);
         device.open();
 
-        var usbInterface = device.interface(0);
+        let usbInterface = device.interface(0);
 
         // https://github.com/tessel/node-usb/issues/147
         // The function 'isKernelDriverActive' is not available on Windows and not even needed.
@@ -17,15 +17,15 @@ exports = module.exports = {
         }
         usbInterface.claim();
 
-        var endpointIn = usbInterface.endpoints[0];
-        var endpointOut = usbInterface.endpoints[1];
+        let endpointIn = usbInterface.endpoints[0];
+        let endpointOut = usbInterface.endpoints[1];
         return [endpointIn, endpointOut];
     },
 
-    bufferToString: function(buffer) {
-        var str = '';
-        for (var i = 0; i < buffer.length; i++) {
-            var hex = buffer[i].toString(16) + ' ';
+    bufferToString: buffer => {
+        let str = '';
+        for (let i = 0; i < buffer.length; i++) {
+            let hex = buffer[i].toString(16) + ' ';
             if (hex.length <= 2) {
                 hex = '0' + hex;
             }