The HonlPhoto 1/4" Speed Grid is part of the Honl Speed System, which allows you to add a line of different light modifiers to your flash unit. The 1/4" Speed Grid attaches to the Speed Strap (offered separately), and dramatically narrows the beam of light that's put out by your shoe mount or handle mount flash. The effect is a small circle of light, with the size depending on flash-to-subject distance.
Two versions are available, one with 1/4" grids and one with 1/8" grids. The 1/8" version produces a spot a few degrees narrower then the 1/4" version.