Boots

I can't find any references to this slide rule on the net. Made in Germany, it bears a "Boots" logo, but not the tri-circle one of Ringplan rules. The number "776" is stamped on the back; I don't know if it's a model number.

It appears to be very much like a Faber Castell 57/87, except that the A/B and C/D scales are extended at both ends, and the cursor has only a single hairline.

It bears scales K,A[B,CI,C]D,L on the front, and S,ST,T on the reverse of the slide. Oddly, there are no hairlines for the trig scales; it's not that they've come off, but rather that there's nowhere they could have been mounted. The top is a 27cm ruler.

It was very dirty when I bought it. Water had apparently been trapped under the cursor at some time, and the metal compression spring there rusted, staining the plastic. After a thorough cleaning, most of the rust came off leaving only light brown stain from around 20 to 23 cm.