Wavelength insensitive couplers can be thought of as "power" splitters and combiners. WDMs can be thought of as "wavelength" splitters and combiners. Several transmitters can be connected to the same antenna using filters called "combiners". Many designs of power splitter can be used in reverse, whereupon they become power combiners. Up to 8&colon;1 combiners are found in micro and pico cells only. These chips added support for texture combiners allowing support for OpenGL 1.3. The PACT Programming Model does also support optional Combiners, e.g. for partial aggregations. Other combiners were created for the series too, such as Landfill and Rail Racer.