This one's kinda an unusual rule. Notice there's only one scan here, while most of my other rules are scanned front and back. In this case, there was no reason to scan the back of the rule 'cause there's nothing printed on it. It's a simplex trig rule on a duplex body. In an interesting approach to economizing, it seems lutz made exactly one style of rule, then simply printed different scales on the rule (including possibly printing on the back) based on the model number. One wonders how much more expensive, for example, was the 252 than this rule, which is identical to it in every respect except the case and the scale arrangement. Interesting note: the end of the slide says "U.S.", while the end of the body says "Made in Japan".