Check the listing for details. TRS 80 Model I Switching Power Supply. Listed at 60.00 USD. This is a modern version of the TRS 80 model I power supply brick. This PS weights just 10 oz including the wall wart. It runs much cooler and is totally silent. Bring your beloved M1 into the modern era with this outstanding power supply or breath life into that M1 that has lost its power supply and needs a new lease on life.