Many people avoid using a camera flash because it washes people out, creates harsh shadows, and usually overpowers the background of the photo. You want to take better pictures under water, so you need a diffuser for your strobe. The Sea Sea Diffusers for YS-D1 Strobe will give you better contrast and richer colors when taking pictures. The diffusers attach easily above and below the water. The diffusers are made from noncorrosive plastic materials. Use of the accessory diffuser softens the light and helps reduce backscatter. So, take better pictures with a diffuser on you strobe. In macro photography when a wide beam is not necessary, no diffuser should be attached. For an even strong circular 100#176; x 100#176; light output is desired, mount the diffuser 100. When a wide-angle lens is used, the Diffuser 120 should be attached. Three beam angles can be selected in accordance with the photographer's requirements. The color temperature of 5,600#176;K is reduced to a color temperature w/diffuser of 5,250#176;K.