Here is a picture of my non-calculator Calculator. I do think it is very rare. I saw it pictured in the catalog page Jeff displayed and I always liked the look of it but I doubted I would ever own one. Then last year one came up on ebay and I won it.

A few knowledgeable Heuer collectors (more knowledgeable than me) have told me they have not seen one in 10-20 years of collecting so I guess it is super rare. However, rarity and value are not the same. The 1133B Monaco comes up regularly on ebay but it is super expensive, because many people, not just Heuer collectors, want to own one. I don't think that many people (besides me, and a few other Heuer nuts) dream of owning an MHT Calculator.

But enjoy it, it is a great watch. Actually I would recommend owning all the watches on the page of the catalog that Jeff showed - I like the Calcs but the cal12 Silverstone is my favourite Heuer.