The YS-D1 Strobe Diffuser 120 from Sea & Sea softens the light of your flash, making it less harsh and reducing reflection for better image quality. It increases the beam angle of your YS-D1 strobe light from 80 x 80° to 120 x 120°. The diffuser also gives the light a color temperature of 5250K. It provides a guide number of 20 on land at ISO 100. It's best used when you are using a wide-angle lens.