diff --git a/Filer-Redis-Setup.md b/Filer-Redis-Setup.md
index 3d30bd9..b621bdc 100644
--- a/Filer-Redis-Setup.md
+++ b/Filer-Redis-Setup.md
@@ -27,7 +27,7 @@ Compared to `redis2`, there are extra Redis operations to maintain this list:
 * Adding or deleting needs one additional lock operation.
 * Updating an entry needs to takes `O(log(N))` times to access the skip list item first.
 
-One Redis operation cost 25 microseconds. The extra Redis operations cost about 100 microseconds when run with 1 million items. It is relatively a tiny cost to pay compared to the whole file creation/update/deletion process. 
+One Redis operation costs about 25 microseconds. The extra Redis operations cost about 4 Redis round trips when running with 1 million items. The cost is relatively small compared to the whole file creation/update/deletion process. 
 
 # Note
 The file read operation is still just one Redis operation, since it does not need to read the list of other directory items.
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