diff --git a/lib/collector.class.js b/lib/collector.class.js
index e9ee3d13..d13466f8 100644
--- a/lib/collector.class.js
+++ b/lib/collector.class.js
@@ -10,9 +10,9 @@ class Collector {
   // Collector constructor
   //   expected - <number> | <string[]>, count or keys
   constructor(expected) {
-    this.expectKeys = Array.isArray(expected) ? new Set(expected) : null;
+    this.expectKeys = Array.isArray(expected) ? expected : null;
     this.expected = this.expectKeys ? expected.length : expected;
-    this.keys = new Set();
+    this.keys = [];
     this.count = 0;
     this.timer = null;
     this.onDone = common.emptiness;
@@ -27,17 +27,17 @@ class Collector {
       this.finalize(err, this.data);
       return this;
     }
-    if (this.expectKeys && !this.expectKeys.has(key)) {
+    if (this.expectKeys && !this.expectKeys.includes(key)) {
       if (this.isDistinct) {
         const err = new Error(UNEXPECTED_KEY + key);
         this.finalize(err, this.data);
         return this;
       }
-    } else if (!this.keys.has(key)) {
+    } else if (!this.keys.includes(key)) {
       this.count++;
     }
     this.data[key] = value;
-    this.keys.add(key);
+    this.keys.push(key);
     if (this.expected === this.count) {
       this.finalize(null, this.data);
     }
diff --git a/lib/collector.functor.js b/lib/collector.functor.js
index 99330c83..eb4fbc29 100644
--- a/lib/collector.functor.js
+++ b/lib/collector.functor.js
@@ -13,7 +13,7 @@ const collect = expected => {
   if (!(isCount || isKeys)) throw new TypeError(TYPE_ERROR);
   let keys = null;
   if (isKeys) {
-    keys = new Set(expected);
+    keys = expected;
     expected = expected.length;
   }
   let count = 0;
@@ -26,7 +26,7 @@ const collect = expected => {
   const collector = (key, err, value) => {
     if (isDone) return collector;
     if (!isDistinct || !(key in data)) {
-      if (!isCount && !keys.has(key)) return collector;
+      if (!isCount && !keys.includes(key)) return collector;
       count++;
     }
     if (err) {
diff --git a/lib/collector.js b/lib/collector.js
index 81034dcc..2c9e3ee7 100644
--- a/lib/collector.js
+++ b/lib/collector.js
@@ -9,9 +9,9 @@ const COLLECT_CANCELED = 'Metasync: Collector cancelled';
 // Data collector
 //   expected - <number> | <string[]>, count or keys
 function Collector(expected) {
-  this.expectKeys = Array.isArray(expected) ? new Set(expected) : null;
+  this.expectKeys = Array.isArray(expected) ? expected : null;
   this.expected = this.expectKeys ? expected.length : expected;
-  this.keys = new Set();
+  this.keys = [];
   this.count = 0;
   this.timer = null;
   this.onDone = common.emptiness;
@@ -32,17 +32,17 @@ Collector.prototype.collect = function(key, err, value) {
     this.finalize(err, this.data);
     return this;
   }
-  if (this.expectKeys && !this.expectKeys.has(key)) {
+  if (this.expectKeys && !this.expectKeys.includes(key)) {
     if (this.isDistinct) {
       const err = new Error(UNEXPECTED_KEY + key);
       this.finalize(err, this.data);
       return this;
     }
-  } else if (!this.keys.has(key)) {
+  } else if (!this.keys.includes(key)) {
     this.count++;
   }
   this.data[key] = value;
-  this.keys.add(key);
+  this.keys.push(key);
   if (this.expected === this.count) {
     this.finalize(null, this.data);
   }
diff --git a/lib/collector.prototype.js b/lib/collector.prototype.js
deleted file mode 100644
index 1a4617ff..00000000
--- a/lib/collector.prototype.js
+++ /dev/null
@@ -1,134 +0,0 @@
-'use strict';
-
-const common = require('@metarhia/common');
-
-function Collector() {}
-
-const COLLECT_TIMEOUT = 'Metasync: Collector timed out';
-
-// Add event listener
-//   eventName - <string>
-//   listener - <Function>, handler
-//
-// Example:
-// const collector = new Collector();
-// collector.on('error', (err, key) => { ... });
-// collector.on('timeout', (err, data) => { ... });
-// collector.on('done', (errs, data) => { ... })
-Collector.prototype.on = function(eventName, listener) {
-  if (eventName in this.events) {
-    this.events[eventName] = listener;
-  }
-};
-
-// Emit Collector events
-//   eventName - <string>
-//   err - <Error> | <null>
-Collector.prototype.emit = function(eventName, err, data) {
-  const event = this.events[eventName];
-  if (event) event(err, data);
-};
-
-// Create new DataCollector
-// Signature: expected[, timeout]
-//   expected - <number>, count of `collect()` calls expected
-//   timeout - <number>, collect timeout, optional
-//
-// Returns: <DataCollector>
-const DataCollector = function(expected, timeout) {
-  this.expected = expected;
-  this.timeout = timeout;
-  this.count = 0;
-  this.data = {};
-  this.errs = [];
-  this.events = {
-    error: null,
-    timeout: null,
-    done: null,
-  };
-  if (this.timeout) {
-    this.timer = setTimeout(() => {
-      const err = new Error(COLLECT_TIMEOUT);
-      this.emit('timeout', err, this.data);
-    }, timeout);
-  }
-};
-
-common.inherits(DataCollector, Collector);
-
-// Push data to collector
-//   key - <string>, key in result data
-//   data - <Object> | <Error>, value or error
-DataCollector.prototype.collect = function(key, data) {
-  this.count++;
-  if (data instanceof Error) {
-    this.errs[key] = data;
-    this.emit('error', data, key);
-  } else {
-    this.data[key] = data;
-  }
-  if (this.expected === this.count) {
-    if (this.timer) clearTimeout(this.timer);
-    const errs = this.errs.length ? this.errs : null;
-    this.emit('done', errs, this.data);
-  }
-};
-
-// Key Collector
-// Signature: keys[, timeout]
-//   keys - <string[]>
-//   timeout - <number>, collect timeout, optional
-//
-// Returns: <DataCollector>
-//
-// Example: new KeyCollector(['config', 'users', 'cities'])
-const KeyCollector = function(keys, timeout) {
-  this.isDone = false;
-  this.keys = keys;
-  this.expected = keys.length;
-  this.count = 0;
-  this.timeout = timeout;
-  this.data = {};
-  this.errs = [];
-  this.events = {
-    error: null,
-    timeout: null,
-    done: null,
-  };
-  const collector = this;
-  if (this.timeout) {
-    this.timer = setTimeout(() => {
-      const err = new Error(COLLECT_TIMEOUT);
-      collector.emit('timeout', err, collector.data);
-    }, timeout);
-  }
-};
-
-common.inherits(KeyCollector, Collector);
-// Collect keys and data
-//   key - <string>
-//   data - <scalar> | <Object> | <Error>, value or error
-KeyCollector.prototype.collect = function(key, data) {
-  if (this.keys.includes(key)) {
-    this.count++;
-    if (data instanceof Error) {
-      this.errs[key] = data;
-      this.emit('error', data, key);
-    } else {
-      this.data[key] = data;
-    }
-    if (this.expected === this.count) {
-      if (this.timer) clearTimeout(this.timer);
-      const errs = this.errs.length ? this.errs : null;
-      this.emit('done', errs, this.data);
-    }
-  }
-};
-
-KeyCollector.prototype.stop = function() {};
-
-KeyCollector.prototype.pause = function() {};
-
-KeyCollector.prototype.resume = function() {};
-
-module.exports = { DataCollector, KeyCollector };
diff --git a/tests/load/collect.js b/tests/load/collect.js
index 16ff5b99..441bd408 100644
--- a/tests/load/collect.js
+++ b/tests/load/collect.js
@@ -5,7 +5,7 @@ const COUNT = 1000000;
 const benchmark = require('./benchmark.js');
 const metasync = require('../../lib/collector.js');
 
-const CollectPrototype = done => {
+const Collect = done => {
   const dc = metasync.collect(6);
   dc.done(done);
   let i = 0;
@@ -17,4 +17,4 @@ const CollectPrototype = done => {
   setImmediate(() => dc.pick('6th', 'key' + ++i * 2));
 };
 
-benchmark.do(COUNT, [CollectPrototype]);
+benchmark.do(COUNT, [Collect]);
diff --git a/tests/load/collect.prototype.js b/tests/load/collect.prototype.js
deleted file mode 100644
index a87a3f0a..00000000
--- a/tests/load/collect.prototype.js
+++ /dev/null
@@ -1,20 +0,0 @@
-'use strict';
-
-const COUNT = 1000000;
-
-const benchmark = require('./benchmark.js');
-const metasync = require('../../lib/collector.prototype.js');
-
-const CollectOldPrototype = done => {
-  const dc = new metasync.DataCollector(6);
-  dc.on('done', done);
-  let i = 0;
-  setImmediate(() => dc.collect('uno', ++i * 2));
-  setImmediate(() => dc.collect('due', ++i * 3));
-  setImmediate(() => dc.collect('tre', ++i * 5));
-  setImmediate(() => dc.collect('4th', 'key' + ++i));
-  setImmediate(() => dc.collect('5th', ++i === 5));
-  setImmediate(() => dc.collect('6th', 'key' + ++i * 2));
-};
-
-benchmark.do(COUNT, [CollectOldPrototype]);
diff --git a/tests/load/run.sh b/tests/load/run.sh
index 5099a681..1d51f0fb 100755
--- a/tests/load/run.sh
+++ b/tests/load/run.sh
@@ -15,5 +15,4 @@ echo
 echo Collector: 1mnl
 node tests/load/collect.js
 node tests/load/collect.class.js
-node tests/load/collect.prototype.js
 node tests/load/collect.functor.js