Clutch The KTM 250 EXC-F employs the KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket and extremely heat resistant clutch plates and new, nitrated steel liners. This clever design employs a diaphragm spring instead of the usual coil springs, making for considerably easier clutch action.
The difference between active and passive solar water heating systems is that active systems have circulating pumps and controls, while passive systems do not. Although passive systems are usually not as expensive as active systems and can last longer, they are generally less eficient.
Tankless or demand-type water heaters heat water directly without the use of a storage tank. Heat pump water heaters move heat from one place to another instead of generating heat directly for providing hot water. Solar water heaters use the sun's heat to provide hot water.