diff --git a/.gitignore b/.gitignore
index 341be631..31d7d6e1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ msgpack/*.cpp
 /tags
 /docs/_build
 .cache
+uv.lock
diff --git a/msgpack/_unpacker.pyx b/msgpack/_unpacker.pyx
index e0cdde43..26fb377e 100644
--- a/msgpack/_unpacker.pyx
+++ b/msgpack/_unpacker.pyx
@@ -222,7 +222,7 @@ cdef class Unpacker:
         If specified, unpacker reads serialized data from it and `.feed()` is not usable.
 
     :param int read_size:
-        Used as `file_like.read(read_size)`. (default: `min(16*1024, max_buffer_size)`)
+        Used as `file_like.read(read_size)`. Must be equal to or smaller than *max_buffer_size*.
 
     :param bool use_list:
         If true, unpack msgpack array to Python list.
diff --git a/msgpack/fallback.py b/msgpack/fallback.py
index 860d94ac..824f59d5 100644
--- a/msgpack/fallback.py
+++ b/msgpack/fallback.py
@@ -137,7 +137,7 @@ class Unpacker:
         If specified, unpacker reads serialized data from it and `.feed()` is not usable.
 
     :param int read_size:
-        Used as `file_like.read(read_size)`. (default: `min(16*1024, max_buffer_size)`)
+        Used as `file_like.read(read_size)`. Must be equal to or smaller than *max_buffer_size*.
 
     :param bool use_list:
         If true, unpack msgpack array to Python list.