The Hood Hat-PK Micro from OP/TECH USA is designed to protect pancake lenses from dust, moisture and impact. Its black neoprene construction offers more protection from moisture than a standard lens cap and because it fits over the entire lens, dust and sand are prevented from finding their way into the lens rings and mount. Also, the Hood Hat will stretch to fit over a lens hood, it can therefore be left on during a photo session and easily removed right before you shoot.
Pancake lenses are becoming more common because they match well with the growing number of compact interchangeable lens "mirrorless" cameras. They are often less than 1" (2.5 cm) deep and the Hood Hat-PK Micro is designed with a non-skid interior surface to grip the sides of these shallower lenses and stay put.