That's a "vintage" Fenix TA21... I wish I could fit an 18650 battery in that thing... Or even better, they'd make an identical one that takes 21700... : r/flashlight
Fenix Switch TK09, TK11 R5, TK12, TK15, TA20 en TA21 | Advantageously shopping at Knivesandtools.com
Fenix TA21 (Q5) Variable Output Tactical LED Flashlight, Strobing, 225 Max Lumens - KnifeCenter - Discontinued
Fenix Flashlight Diffuser Tip AD102-W Large FOR TK11, TK12, TA20, TA21, | eBay