Full Details

Name and Model Number Patco Mark IV Data Log
Country of Origin U.S.A.
Date of Manufacture  
Front Scales K, Sq-odd, Sq-even, A, [ B, T, ST, S, C, ] D, DI, Th, Sh2, Sh1
Back Scales LL0LL0+, LL0-, LL1+, LL1-, DF, [ CF, CIF, L, CI, C, ] D, LL2+, LL2-, LL3+, LL3-
Scale Length 24.8 cm
Type of Rule Slide Rule
Construction Plastic
Area of Use Generic
Rarity RRR
Donor Collection of Rod Lovett
Match Number 23

RR = Rare -- 1 of 25 collectors has one; it may take a year to find an example in the marketplace.   
RRR = Very rare -- only very few known to collectors; may take several years before one comes up for sale.   
RRRR = Extremely rare -- a museum piece; unlikely that an example will ever come up for sale.