For use on rounded 23mm window sill boards. This plastic corner joint is doubleended so one piece can be used to join two window sill internal corners . One end is used for 90 corners while the other which is designed for 135 corners can be used to fit anything from 120150 corners . This internal corner joint is for use on rounded 23mm window sill boards its ideal for laminated window boards. Features & Benefits Available in three popular colours they are a great choice for matching with existing window sills. Chocolate Brown end cap can be used with Mahogany and Rosewood laminated window sills while Caramel is idea for Oak Light Oak and Sherwood laminated window sills