Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – Astrolux S41S/S42S Flashlight Extension Tube Silver (-3 USD)
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (11.63 USD): BGAlerabat15
Coupon (12.31 USD): BGtorch2
(CouponsFromChina.com tip: just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): AXMAS, BGAB20, BGASTROLUX, BGAST25, BGAFF10OFF, BGCuponation10, 13f142, 4BLF, BG10OFFAFF, BGwhielabel, BG10OFFAFF1, BANGGOODSD, BGTorch4, 00c906, BGtorch3, BGtorch7, BGAlerabatI
(there’s a little possibility that old coupon will work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – Astrolux S41S/S42S Flashlight Extension Tube Silver (-3 USD)
Price history and price alert
Here is price history (for all/most countries) for Astrolux S41S/S42S Flashlight Extension Tube Colored.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).