Dimensions:

18mm:
Length: Piece 1: 12cm. Piece 2 8.5cm
Width 18mm with a 1mm taper to 17mm

20mm
Length: Piece 1 12.5cm. Piece 2: 9cm
Width: 20mm with a 2mm taper to 18mm

22mm:
Length: Piece 1: 13cm. Piece 2: 9cm
Width: 22mm with a 2mm taper to 20mm