Morris Midi DC Slave Flash Di, for Digital Cameras, Guide Number 42 with ISO 100 in Feet. Dual-mode Wireless Slave Flash: N-mode for single flash triggered by your camera's flash and syncs with main flash P-mode for cameras with pre-flash triggered by your camera's main flash, not the the pre-flash and syncs. Compact & powerful! 1/4-20 Threaded Socket for Tripod Mount. Dimensions: 1.2" x 2.4" x 2.5" Power Source: 2 AA Size Batteries