Keufell & Esser Merchants Rule
Here is the user manual for model N4095:
ISRM_M394_KE_4095-3_Merchants_SlideRule_Instructions_DonaldSBachelorCollection.pdf
Click on the next link to see professional panoramic pictures of the N4096 and N4095 models
Click on the next link to see professional panoramic pictures of the N4096 and N4095 models