Option passed to a control to give it an absolute width.

	// Draws a  button with a  fixed width
	function OnGUI() {
		GUILayout.Button("A Button with fixed width", GUILayout.Width(300));
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void OnGUI() {
        GUILayout.Button("A Button with fixed width", GUILayout.Width(300));
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def OnGUI() as void:
		GUILayout.Button('A Button with fixed width', GUILayout.Width(300))