The ribosome uses several interactions to improve the accuracy of pairing between the codon and the anticodon. The first codon-anticodon base pair interacts with G1493, which forms interactions with both sides of the base pair. This interaction effectively measures the width of the base pair, and disfavors wider or narrower mispaired options. The second codon-anticodon base pair forms a similar interaction with two ribosome bases, which again measure the width of the base pair. The third codon-anticodon base pair only has one small interaction, which supports the flat face of the anticodon base. However, this is not a problem, since the third position must be allowed to 'wobble' and form non-standard base pairs.