This roof mount will be as long lasting as your weathervane. It can be easily adjusted to fit your roof or cupola. It fits Good Directions standard size weathervanes and accepts up to 3/4" diameter weathervane poles. The mounting plates measure: 3-3/4-Inch x 3-3/4-Inch with 4 mounting holes per plate. The dimensions are: 12-Inch L x 4-Inch W x 7-Inch H.