During the 1970s, HEUER-LEONIDAS created ranges of economical stopwatches. The most popular are the ref.8042 and ref.8047 of the TrackMaster family. A HEUER catalog from the 70s announces 100,000 units sold in one year! 
These plastic case stopwatches were not too expensive: $22 in 1972  , half the price of the cheapest stopwatch found in the same catalog. To give you an idea of prices in 1973, a McDonald’s cheeseburger cost $0.33  .
Models 8042 and 8047 were introduced as general-purpose stopwatches. However, the 8047, a 1/5th of a second stopwatch, has a special register to help timing different sports. The 8042 is more accurate; giving time with a precision of 1/10th second .
Clearly, their 1 jewel pinlever mechanism (8040 and 8045 calibers) is not regulated as a 7-jewels jellewed lever mechanism. However, a duration of -1/+3 seconds  per hour is enough to time daily or non-professional sports activities . The blue 8047 of the video has been tested with +1.5s/+2s per hour . This is pretty good for a 40-year-old ” inexpensive ” stopwatch!
All TrackMasters are controlled by 3 pushers: the central green crown to start and continue, the left red pushers to stop and the right black pushers to stop.
The brightly colored plastic cases are fun and far from the classic stopwatch design. 5 colors are available: white, black, red, blue and silver. No doubt they were produced in the 70s!
They look a bit like toys  … Was HEUER designed for children?  Maybe … A vintage advertisement in the comic book magazine “Le journal de Tintin” promotes the TrackMaster. “Do you have your LEONIDAS TrackMaster” to time your favorite driver” asks the ad as if the interlocutor was a 10 years old boy. By the way, the ad does not say “HEUER TrackMaster” but “LEONIDAS” TrackMaster. The TrackMaster 8042 and 8047 are one of the few models (perhaps the only ones) signed LEONIDAS, after the company was bought by HEUER in 1964.
The plastic cases (except for the black fiber case) have been widely used for the economical stopwatch lines: CAN-AM, clubmaster and super sport. At the end of the 70s, HEUER added the references 8032 and 8037 which are similar to the 8042 and 8047 but with a classic metal case.
,  see onthedash.com 1972 catalog (page 8)
 see tasteofhome.com
 see onthedash.com 1973 catalog (page 4)
 personnal autor suggestion, made after reading HEUER’s offical catalogs and ads for the trackmaster stopwatches
 test made by autor : stopwatch placed horizontally
,  personnal autor suggestion