Coming soon to our shelves will be a neat new product from Rogue, called appropriately enough the Rogue Grid. The Rogue Grid is a stackable grid system for your hotshoe flash. There's a bevel/holder, into which you can slot either of two grids, or both. You can see the grids are slotted, so they keep proper alignment, which means in a very tiny package, you have the option of three different grid tightnesses (45, 25, and 16 degrees).
The grid holder is all of 1.2" deep, and the whole package with the adjustable tension strap for mounting it to your flash weighs just 3.5oz, which makes this one of those no-brainer tip-ins for your field kit. And, just in case you're wondering why you'd want a grid, the picture below does a pretty good job of showing just how the progressively tighter grids affect your light output.
Pricing will be coming soon, as will their presence on our website. Keep your eyes peeled.