The Nissin i40 Four Thirds Flashgun is a versatile and powerful accessory for digital cameras, DSLRs, and camcorders. With a guide number of 40m, this flash gun is compatible with various brands including Canon, Panasonic, Olympus, Nikon, and Fujifilm. Its features such as built-in diffuser, rapid-fire mode, flash exposure compensation, and S-TTL / E-TTL functionality make it a valuable tool for photographers looking to capture high-quality images. The flash gun also boasts an LCD display, swivel and tilt capabilities, as well as an AF assist light for added flexibility in various shooting situations.