YONGNUO External Flash Battery Pack SF-18 for Nikon SB-800 SB-28DX SB-28 SB-27 SB-26 &lt;BR&gt;Specification: This external flash battery pack is an external power source for the Nikon Speedlight. &lt;BR&gt; &lt;BR&gt;This Battery Pack can hold 8 AA-type batteries, ensuring a stable power supply for the speedlite, greatly increasing the number of flashes, and reducing recycling time.&lt;BR&gt; &lt;BR&gt;Package Includes: 1 x External Flash Battery Pack (batteries not included) 1 x Padded protective case 1 x 1/4 inch screw adaptor & English and Chinese instructions&lt;BR&gt; &lt;BR&gt;Note: Depending on state of battery charge; Maximum of 15 consecutive shots without break or risk of overheating&lt;BR&gt; &lt;BR&gt;Compatible with Nikon SB-800 SB-28DX SB-28 SB-27 SB-26, for Yongnuo Flash Speedlite YN-560 YN-565EX YN-580EX II YN-580EX&lt;BR&gt;