diff --git a/src/mol-data/int/ordered-set.ts b/src/mol-data/int/ordered-set.ts
index e9abea2264565e9851ceed5cd4f2fab56a36f483..038b11830d67371ac9c90f50b2c8ac403f274a03 100644
--- a/src/mol-data/int/ordered-set.ts
+++ b/src/mol-data/int/ordered-set.ts
@@ -8,6 +8,7 @@ import * as Base from './impl/ordered-set'
 import Interval from './interval'
 import SortedArray from './sorted-array';
 
+/** test */
 namespace OrderedSet {
     export const Empty: OrderedSet = Base.Empty as any;
     export const ofSingleton: <T extends number = number>(value: T) => OrderedSet<T> = Base.ofSingleton as any;
@@ -50,7 +51,8 @@ namespace OrderedSet {
     }
 }
 
-type OrderedSet<T extends number = number> = Interval<T> | SortedArray<T>
-//{ '@type': 'int-interval' | 'int-sorted-array' }
+/** Represents bla */
+type OrderedSet<T extends number = number> = SortedArray<T> | Interval<T>
+
 
 export default OrderedSet
\ No newline at end of file
diff --git a/src/mol-model/structure/query/selection.ts b/src/mol-model/structure/query/selection.ts
index 5bd8f76261ec1ebbf5465909454d845bd4060256..d554a3bf46ef0401cdda250a77d6a4449ef0c14f 100644
--- a/src/mol-model/structure/query/selection.ts
+++ b/src/mol-model/structure/query/selection.ts
@@ -36,7 +36,7 @@ namespace Selection {
     }
 
     export function toLoci(sel: Selection): Element.Loci {
-        const loci: { unit: Unit, indices: Element.Indices }[] = [];
+        const loci: { unit: Unit, indices: OrderedSet<Element.Index> }[] = [];
         const { unitMap } = sel.source;
 
         for (const unit of unionStructure(sel).units) {
diff --git a/src/mol-model/structure/structure/element.ts b/src/mol-model/structure/structure/element.ts
index c9add11f99f5cc42cc12c33edfc24cf1f6344719..819d17687ebacafb5e48a0fd4abf885876b9d9a1 100644
--- a/src/mol-model/structure/structure/element.ts
+++ b/src/mol-model/structure/structure/element.ts
@@ -15,7 +15,6 @@ namespace Element {
 
     /** Index into Unit.elements */
     export type Index = { readonly '@type': 'element-index' } & number
-    export type Indices = OrderedSet<Index>
 
     /** All the information required to access element properties */
     export interface Location<U = Unit> {
@@ -48,11 +47,11 @@ namespace Element {
              * Indices into the unit.elements array.
              * Can use OrderedSet.forEach to iterate (or OrderedSet.size + OrderedSet.getAt)
              */
-            indices: Indices
+            indices: OrderedSet<Index>
         }>
     }
 
-    export function Loci(elements: ArrayLike<{ unit: Unit, indices: Indices }>): Loci {
+    export function Loci(elements: ArrayLike<{ unit: Unit, indices: OrderedSet<Index> }>): Loci {
         return { kind: 'element-loci', elements: elements as Loci['elements'] };
     }