After we started our Desert Racing products I saw an obvious need for these, up til now there really hasn't been a strong perch made for a SUA application. Now there is! We make these to our high standards but there are some substantial differences between these and all of our other perches. These are fully boxed and only 4 3/4" long, just enough to support the spring but not enough to hinder flex. Because they are fully boxed they can be made of 3/16" steel rather than our standard 1/4". These are sold in pairs and you choose the axle diameter, 3", 3.25", or 3.5". BTW, these work perfect in a SOA application involving extreme travel springs.