diff --git a/stdlib/zlib.pyi b/stdlib/zlib.pyi
index 646c96bd2..2954a8402 100644
--- a/stdlib/zlib.pyi
+++ b/stdlib/zlib.pyi
@@ -2,28 +2,28 @@ from array import array
 from typing import Any
 from typing_extensions import Literal
 
-DEFLATED: int
-DEF_MEM_LEVEL: int
+DEFLATED: Literal[8]
+DEF_MEM_LEVEL: int  # can change
+DEF_BUF_SIZE: Literal[16384]
 MAX_WBITS: int
-ZLIB_VERSION: str
+ZLIB_VERSION: str  # can change
+ZLIB_RUNTIME_VERSION: str  # can change
 Z_NO_COMPRESSION: Literal[0]
 Z_PARTIAL_FLUSH: Literal[1]
-Z_BEST_COMPRESSION: int
-Z_BEST_SPEED: int
+Z_BEST_COMPRESSION: Literal[9]
+Z_BEST_SPEED: Literal[1]
 Z_BLOCK: Literal[5]
-Z_DEFAULT_COMPRESSION: int
-Z_DEFAULT_STRATEGY: int
-Z_FILTERED: int
-Z_FINISH: int
-Z_FIXED: int
-Z_FULL_FLUSH: int
-Z_HUFFMAN_ONLY: int
-Z_NO_FLUSH: int
-Z_RLE: int
-Z_SYNC_FLUSH: int
+Z_DEFAULT_COMPRESSION: Literal[-1]
+Z_DEFAULT_STRATEGY: Literal[0]
+Z_FILTERED: Literal[1]
+Z_FINISH: Literal[4]
+Z_FIXED: Literal[4]
+Z_FULL_FLUSH: Literal[3]
+Z_HUFFMAN_ONLY: Literal[2]
+Z_NO_FLUSH: Literal[0]
+Z_RLE: Literal[3]
+Z_SYNC_FLUSH: Literal[2]
 Z_TREES: Literal[6]
-DEF_BUF_SIZE: int
-ZLIB_RUNTIME_VERSION: str
 
 class error(Exception): ...