diff --git a/src/monitor_utils/constants.py b/src/monitor_utils/constants.py
index 3b0f7b0..d018ae2 100644
--- a/src/monitor_utils/constants.py
+++ b/src/monitor_utils/constants.py
@@ -33,20 +33,8 @@ FAILURE_DELAY = 3
 
 TIMEOUT_SECONDS = 30
 CYCLE_TIMEOUT_SECONDS = 600
-# curl_cffi's AsyncSession defaults to 10 handles and blocks on an untimed
-# pool.get() past that, so a monitor fanning out wider silently serialises with
-# no timeout covering the wait. Handles are allocated lazily (the pool holds
-# None placeholders until popped), so a generous ceiling costs a low-concurrency
-# monitor nothing. Monitors fanning out past this pass max_clients explicitly.
 MAX_CURL_HANDLES = 64
-# Budget for closing a session. curl_cffi's close awaits the multi handle with
-# no timeout of its own, so a wedged transfer would otherwise park whatever is
-# closing the session, including an `async with` exit.
 SESSION_CLOSE_TIMEOUT_SECONDS = 10
-# Explicit curl_cffi profiles rather than the "chrome" / "chrome_android"
-# aliases, which float to the newest build (chrome146 / chrome131_android in
-# curl_cffi 0.15). Chrome 116, 123 and everything from 133a up were refused by
-# B&H's Cloudflare on every try (2026-09-26); the ones listed passed.
 CLIENT_IDENTIFIERS = [
     "chrome119",
     "chrome120",
diff --git a/src/monitor_utils/runner.py b/src/monitor_utils/runner.py
index d1c2a0f..c8f3e19 100644
--- a/src/monitor_utils/runner.py
+++ b/src/monitor_utils/runner.py
@@ -6,6 +6,7 @@ from contextlib import asynccontextmanager, nullcontext
 import aiohttp
 from aioproxies import AioProxies
 from curl_cffi.requests import AsyncSession
+from curl_cffi.requests.impersonate import BrowserTypeLiteral
 from log_setup import setup_logging
 from motor.motor_asyncio import AsyncIOMotorCollection
 from motor.motor_asyncio import AsyncIOMotorClient
@@ -377,6 +378,7 @@ async def run_bounded_cycle(
     session_timeout: int = TIMEOUT_SECONDS,
     max_clients: int = MAX_CURL_HANDLES,
     cycle_timeout: int = CYCLE_TIMEOUT_SECONDS,
+    impersonate: BrowserTypeLiteral | None = None,
     **kwargs,
 ) -> CycleResult | None:
     """Run one monitor cycle on a fresh session under a hard time budget.
diff --git a/src/monitor_utils/sessions.py b/src/monitor_utils/sessions.py
index 7587d51..d18ca1e 100644
--- a/src/monitor_utils/sessions.py
+++ b/src/monitor_utils/sessions.py
@@ -13,6 +13,7 @@ import random
 from aioproxies import AioProxies
 from aioweb import Response
 from aioweb_tls import CurlCffi, TLSSession
+from curl_cffi.requests.impersonate import BrowserTypeLiteral
 from monitor_utils.constants import (
     CLIENT_IDENTIFIERS,
     MAX_CURL_HANDLES,
@@ -70,6 +71,7 @@ def get_default_session(
     headers: dict | None = None,
     timeout: int = TIMEOUT_SECONDS,
     max_clients: int = MAX_CURL_HANDLES,
+    impersonate: BrowserTypeLiteral | None = None,
 ) -> TLSSession:
     """Return a TLSSession impersonating a random client fingerprint.
 
@@ -98,13 +100,17 @@ def get_default_session(
             checkout. Keep it at or above the monitor's real fan-out (the sum
             of its pagination semaphores plus any unsemaphored per-cycle
             requests) so the wait is never reachable.
+        impersonate: A curl_cffi profile to pin instead of drawing one from
+            CLIENT_IDENTIFIERS, for a retailer whose bot protection only
+            tolerates some profiles from a given IP (B&H's Cloudflare refuses
+            every chrome profile on a flagged IP but still accepts safari).
 
     Returns:
         A BoundedCloseSession (a TLSSession whose close is bounded) over a
         curl_cffi backend with a random impersonation, with the proxy pool
         attached as proxy_pool.
     """
-    impersonate = random.choice(CLIENT_IDENTIFIERS)
+    impersonate = impersonate or random.choice(CLIENT_IDENTIFIERS)
     session = BoundedCloseSession(
         backend=CurlCffi(impersonate=impersonate),
         headers=headers,