Holland chiles, aka Dutch chiles, is a variety of Capsicum annuum which were developed in the Netherlands from an Indonesian Cayenne pepper (which is hotter). The Scoville heat scale is 5,000 - 10,000. In addition to red, the chiles can be found in green or yellow, and each grows to be about 4-5" long.
The Holland chile would be the hot pepper of choice for making the Indonesian dish; Beef Rendang. Saveur magazine offers a perfect recipe for this dish here. Other common uses include fresh salsas, soups or stews. The chiles may be pickled too.
If you can't find Holland chiles you can substitute one of these: