A miniature ball valve from Beswich Engineering (Greenland, NH) comes in two configurations. The MBV-1010-303 is for applications requiring an on/off valve, while the MBVT-1010-303 is for applications requiring selecting one of two possible flow paths. The valves weigh 9 and 12 grams, respectively.
Both valves incorporate a stainless steel housing and Buna-N seal material. Options include EPDM and fluorocarbon. Other configurations, including the MBVMD-1010, a three-way mixing, diverting valve, are also available.
For more info, contact http://info.hotims.com/22908-303