Charging time 4000mAh 21700 approximately 1.5 hours, Distance 650m, Charging Type-C fast charging port, Lens Tempered glass lens with violet coating, Body material 6063 aluminum alloy, Lumen 4000LM, Waterproof rating IPX7, Surface Finishing Military Standard Grade 3 Hard Oxide, Spring Copper alloy silver-plated spring with ultra-low internal resistance, Model HK4S, Flashlight net weight 180g, Package Weight 455g, Battery 26800, Color Temperature 6500K (Cool White) and 5000K (Neutral), Switching pressure ring Stainless steel, Color Silver White / Black / Desert Yellow (Optional), Bead Luminus-SST20, 26650 or 21700 (Not included), red light on when charging; blue light on when charging is complete, Product Dimensions 127mm (overall length)x 42mm (head)x 34mm (tail)x 33mm (barrel), Brand HAIKELITE.
You can create price alert here, copy coupons and view price history. What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
1. ($50.35): BG10OFFAFF1
apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BgcLuBofErtA10, BGFLS15, BGAFF10OFF, BGCuponation10, 4BLF, BGHONEY2110, BG10OFFAFF, BGwhielabel, BGflashlight
(there’s a little possibility that old coupon will work)
Price history and price alert
Do you need price history chart (for all/most countries) for HAIKELITE HK4S SST20 Flashlight? There we go. The lowest price was: $50.35.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).