Two Versions are known and referred to here as Version "A" and Version "B".  Both are dated 1938.
 
Version "A"
Folded Dimensions: 3.75" X 10.5"
Open Dimensions: 31" W X 10.5" H
Date Location: In lower right corner beside the Manufacturer's name is the number 38. 
Cover Description: Orange & white cover with green center showing a "Supertest" sign hanging from a frame as would be seen in front of a service station.  Orange, white & and dark green text.
Date Code: "38" on main side, lower right corner
Scale: Both sides - 1" = 18 miles
Main Legend Side Features: Legend, map of Southern Ontario, only as far north as a Wiarton - Bala - Renfrew line, "Morning Check-up" advertisement and a "Look for this Sign" advertisement.  A banner across the top of the map proclaims; "American Money Accepted by Supertest Dealers at Current Rates of Exchange"
Opposite Side Features: Legend, Map of Northern Ontario with Owen Sound on the southern edge, Renfrew on the eastern and Sault Ste. Marie on the north western edge of the map, conservation information, Gold Standard Motor Oil and cover.
Other: Produced by the Map Speciality Company
Note: Thanks to John Torensma for sharing this map from his collection. 
 
Version "B" 
Folded Dimensions: 3.75" X 10.5"
Open Dimensions: 31" W X 10.5" H
Date Location: In lower right corner beside the Manufacturer's name is the number 38.
Date Code: "38" on main side, lower right corner
Cover Description: White and green cover with light brown center showing a "Supertest" logo.  Orange, white and dark green text.
Scale: Both sides - 1" = 18 miles
Main Legend Side Features: Legend, map of Southern Ontario, only as far north as a Wiarton - Bala - Renfrew line, "Morning Check-up" advertisement and a "Look for this Sign" advertisement.  A banner across the top of the map proclaims; "American Money Accepted by Supertest Dealers at Current Rates of Exchange"
Opposite Side Features: Legend, Map of Northern Ontario with Owen Sound on the southern edge, Renfrew on the eastern and Sault Ste. Marie on the north western edge of the map, "Protect Your Investment" information, Gold Standard Motor Oil and cover.
Other: Produced by the Map Speciality Company
Note: Thanks to Dave Goforth for sharing this map from his collection. 

1938A Cover
Version "A"
1938B Supertest Cover
Version "B"

1938 fronts

Comparison of 1938 Version "A" and "B" - Sides with Covers

1938 backs
Comparison of 1938 Version "A" and "B" - Side With Southern Ontario Map
1938 dates
Version "A" and "B" both showing the 1938 date code.
1938A Specialist
Version "A" Page 
 1938A Conservation
Version "A" Gold Standard Advertisement