In March 1975, a similar type of vehicle was introduced in Sweden, the "A tractor" "arbetstraktor" (work tractor); the main difference is an A tractor has a top speed of 30 km/h. This is usually done by fitting two gearboxes in a row and not using one of them. The Volvo Duett was, for a long time, the primary choice for conversion to an EPA or A tractor, but since supplies have dried up, other cars have been used, in most cases another Volvo. The SFRO is a Swedish organization advocating homebuilt and modified vehicles.