My XTAR X4 Extended is able to charge an Olight 18650 (not too surprised). However, it is somehow also able to charge the Olight 21700 despite the plastic ring around the positive
Olight 21700 5000mAh 3.6v Rechargeable Lithium Ion Battery For Sale
Olight modified 21700 works in Fenix PD36TAC. Is there a reason I shouldn't do this? : r/flashlight
Olight Warrior X Turbo Tactical LED Flashlight, Black, 1100 Max Lumens (1 x 21700) - KnifeCenter
Olight Seeker 3 Pro 4200 Lumens Magnetic USB Rechargeable (21700 battery included)
Rechargeable 21700, 5000mAh 3.6v battery - Olight Store