This listing is for a custom battery caddy for Streamlight Survivor flashlights. It replaces the OEM version which holds (4) AA cells and allows for use of (2) 18650 cells configured in parallel to produce 4.2V. The caddy also allows use of both flat-top 18650 cells which are 65mm long and the longer cells with the built in charger which are 70mm long. This caddy design uses the same geometry feature as the OEM to protect against accidentally installation in the wrong direction. Disclaimers: This caddy is only for the Survivor flashlight. If you require a similar caddy for the newer Survivor-X, please check my other listings as they are not compatible.The OEM caddy is configured to operate at 6v with (4) AA cells while my design operates at 4.2v due to the nature of 18650 cells. This voltage difference does not impact the performance of the beam based on my testing. When your 18650 battery requires charging, the cells must be removed from the caddy and charged using a charger designated for 18650 batteries. This auction is for the caddy ONLY and does not include the 18650 batteries, the OEM caddy or Flashlight shown in the pictures. As this is a 3D printed part, there may be some slight blemishes due to the printing process. This in no way weakens or affects the functionality of the caddy.Buy with confidence. This adapter is made in the USA with materials sourced domestically. Please contact me with any questions before ordering. Also if you are looking for other 18650 adapters for D & C cell batteries, please visit my eBay store. Thanks Condition is New. Shipped with USPS First Class Package.