From the very late 60’s, 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! 
The ancestor of these 2 models is the pretty rare ref.8041, found in a 1968 catalog  . However it quickly disappear from HEUER commercial documents, replaced by the 8042.
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 (and 8041) 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 8041, 8042, 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, super sport or roadmaster.
Economical metalic case timers appeared in the second part of the 70’s when HEUER developped new offers for small budgets. New ranges of pinlever stopwatches were launched, some with one jewel movement (trackmate), some with 7 jewels movement (trackstar). The trackmaster familly was completed with the references 8032 and 8037, similar to the 8042 and 8047 but with a classical metal case. Altough, it disappeared quickly from commercial documentation and only branded under Leonidas, the 8041 has also its metalic case version, the hard to find 8031 spotted in few 80’s catalogs.
In 1986, after HEUER has changed for Tag-HEUER (1985), the 8042 and 8047 were replaced by two new design plastic color case economical timers, the 8062 and 8067, sold under the commercial name “super sport”. The 8032 and 8037 were still produced and marketed under the label trackmaster. These trade names were finaly dropped in the early 90’s.
,  see onthedash.com 1972 catalog (page 8)
 see onthedash.com 1968 catalog (page 24)
 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
See also pages on the 8032, 8037, 8041, 8042 and 8047