This corner piece allows you to finish protruding corners perfectly. If you use 1 cm joints, you will require 38 corner pieces if a corner is 250 cm high. Brick height 5.5 cm + 1 cm joint = 6.5 cm. 250 divided by 6.5 = 38 pieces. The inner side of this corner piece measures 22.5 x 9.5 cm. It is 2 cm thick.