The Perst open-source project is available as a free download, though a licence must be purchased for commercial or closed-source products. The object-oriented database comes in Java and C# versions. It has "ACID" properties (atomicity, consistency, isolation, and durability) and supports a fast recovery time for rollbacks. Also, it has a runtime footprint between 30k and 300k, depending on the feature set, including optional garbage collection, automatic schema evolution, and XML import/export utilities. Perst supports a range of data-storage implementations, including B-Tree for reduced disk I/O, R-Tree for spatial data representation, and T-Tree for main-memory database containers. It's integrated with open-source tools like AspectJ and Jassist.