diff --git a/fetch2core/src/main/java/com/tonyodev/fetch2core/DownloadBlock.kt b/fetch2core/src/main/java/com/tonyodev/fetch2core/DownloadBlock.kt
index 4daf95ba..39a77eab 100644
--- a/fetch2core/src/main/java/com/tonyodev/fetch2core/DownloadBlock.kt
+++ b/fetch2core/src/main/java/com/tonyodev/fetch2core/DownloadBlock.kt
@@ -1,19 +1,26 @@
 package com.tonyodev.fetch2core
 
+/** Class used to hold partial downloaded information for a download.*/
 interface DownloadBlock {
 
+    /* Download ID.*/
     val downloadId: Int
 
+    /** Position in the downloading block sequence.*/
     val blockPosition: Int
 
+    /** Block start position.*/
     val startByte: Long
 
+    /* Block end position.*/
     val endByte: Long
-
+    /* Downloaded bytes in block.*/
     val downloadedBytes: Long
 
+    /** Progress completion of block.*/
     val progress: Int
 
+    /** Copy DownloadBlock object.*/
     fun copy(): DownloadBlock
 
 }
\ No newline at end of file