The interior size of these goals are 111mm x 54mm, compared with 125mm x 60mm for set N. The picture above shows the difference between the sizes of Set N and Set NN. Set NN became C149 in 1977, but had left the range by 1981. Both goal types are the same depth - 50mm - so the ball will still stick in the smaller goals. Apart from the depth, all the dimensions seem to be reduced - the posts are thinner, and even the net seems more delicate.