diff --git a/README.md b/README.md
index e6dfc93..f0786d1 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,9 @@ var result = objtree(target, {
   // Prefixed before every name (ex. window)
   grandparent: "",
   
+  // String used to indent lines to display the level of nesting
+  indentstr: "  ",
+  
   // Array of strings (behaving like regular expressions) matched against names to exclude
   // Use / to separate nested objects (ex. {a:{b:{c:true}}} will be a/b/c)
   // Note that grandparent is not included in the name matching process
diff --git a/objtree.js b/objtree.js
index 276f1d9..0144e3a 100644
--- a/objtree.js
+++ b/objtree.js
@@ -14,6 +14,7 @@
   var objtree = function(target, {
     maxlevel = 10,
     grandparent = "",
+    indentstr = "  ",
     exclude = []
   } = {}){
     var excludeRules = exclude.map(rule => new RegExp(rule));
@@ -142,7 +143,7 @@
         
         var addLines = function(node, parents, level){
           let entries = Object.entries(node);
-          let prefix = "  ".repeat(level)+"|-- ";
+          let prefix = indentstr.repeat(level)+"|-- ";
           
           let longest = Math.max.apply(null, entries
             .filter(entry => varTypes.includes(entry[1].type))