diff --git a/scrapy/core/downloader/handlers/http10.py b/scrapy/core/downloader/handlers/http10.py
index 2507a4231..9117cb818 100644
--- a/scrapy/core/downloader/handlers/http10.py
+++ b/scrapy/core/downloader/handlers/http10.py
@@ -3,8 +3,13 @@
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Type
 
+from twisted.internet.defer import Deferred
+
+from scrapy import Request, Spider
+from scrapy.crawler import Crawler
+from scrapy.settings import BaseSettings
 from scrapy.utils.misc import build_from_crawler, load_object
 from scrapy.utils.python import to_unicode
 
@@ -12,29 +17,33 @@ if TYPE_CHECKING:
     # typing.Self requires Python 3.11
     from typing_extensions import Self
 
+    from scrapy.core.downloader.contextfactory import ScrapyClientContextFactory
+    from scrapy.core.downloader.webclient import ScrapyHTTPClientFactory
 
 class HTTP10DownloadHandler:
     lazy = False
 
-    def __init__(self, settings, crawler):
-        self.HTTPClientFactory = load_object(settings["DOWNLOADER_HTTPCLIENTFACTORY"])
-        self.ClientContextFactory = load_object(
+    def __init__(self, settings: BaseSettings, crawler: Crawler):
+        self.HTTPClientFactory: Type[ScrapyHTTPClientFactory] = load_object(
+            settings["DOWNLOADER_HTTPCLIENTFACTORY"]
+        )
+        self.ClientContextFactory: Type[ScrapyClientContextFactory] = load_object(
             settings["DOWNLOADER_CLIENTCONTEXTFACTORY"]
         )
-        self._settings = settings
-        self._crawler = crawler
+        self._settings: BaseSettings = settings
+        self._crawler: Crawler = crawler
 
     @classmethod
-    def from_crawler(cls, crawler) -> Self:
+    def from_crawler(cls, crawler: Crawler) -> Self:
         return cls(crawler.settings, crawler)
 
-    def download_request(self, request, spider):
+    def download_request(self, request: Request, spider: Spider) -> Deferred:
         """Return a deferred for the HTTP download"""
         factory = self.HTTPClientFactory(request)
         self._connect(factory)
         return factory.deferred
 
-    def _connect(self, factory):
+    def _connect(self, factory: ScrapyHTTPClientFactory) -> Deferred:
         from twisted.internet import reactor
 
         host, port = to_unicode(factory.host), factory.port