The diameter listed for the 1974 Belize bronze swallow-tailed kite 1 cent is 19mm, yet when I compared it to an American wheat cent (which is listed on Numista as 19mm) the swallow-tailed kite 1 cent was noticeably larger. Granted, it's less than a millimeter but most certainly worth looking into. I do not possess anything accurate enough to measure its true diameter at this time. If someone would look into this that would be great.
The listed diameter on Numista is inaccurate enough to the point that the Belize 1 cent would not fit into a blank Dansco cent album (designed for American cents).