Advent Calendar
Advent Calendar2021
Illustration · have this car? Upload a photo belowGTD78
Advent Calendar
Hot Wheels Monoposto 2021
The Hot Wheels Monoposto was released in 2021 in the “Advent Calendar” series, toy number GTD78. It is a special release outside the numbered mainline and therefore has no collector number.
- 2021
- GTD78
- Toy #
- GTD78
- Series
- Advent Calendar
- Year
- 2021
- Product line
- Special release (outside the numbered mainline)
- Casting
- Monoposto
- Designer
- Alec Tam
- Color
- Black · black
- Tampo
- Pink, Blue and Grey flames with Hot Wheels Logo
- Base
- Black / Plastic
- Window
- Blue tint
- Interior
- Black
- Wheels
- Grey 10SP · 10 Spoke
- Country
- Indonesia
- Status
- Regular
- Notes
- Base code(s): · Monoposto
Paint: Black; wheels: Grey 10SP (10 Spoke); made in Indonesia.
The Monoposto casting first appeared in 2001 and has 47 releases in our database, most recently in 2025.
The Advent Calendar series of 2021 has 3 cars.
Not unboxed yet
We have not had this car on the channel yet. Request it – the most requested cars get unboxed first.
Collectors & photos
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Collector notes
What collectors know about this car: variants, finds, cards, wheels, colours.
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Frequently asked questions
What is the toy number of the Hot Wheels Monoposto?
The toy number is GTD78 (2021). It is printed on the back of the card.
Which series is the Hot Wheels Monoposto from?
It was released in 2021 as a special release outside the numbered mainline, series “Advent Calendar”.
Is the Hot Wheels Monoposto a Treasure Hunt?
No, it is a regular release.
Has Wheel Wonderland unboxed the Monoposto?
Not yet – you can request it on this page.
Monoposto: 47 versions
The 10 closest versions – see all on the casting page.
| Model | Series | Series # | Toy # | Color | Year | ||
|---|---|---|---|---|---|---|---|
| MonopostoX6999 · Purple | Multi-Pack Exclusives | X6999 | Purple | 2019 | |||
| MonopostoX6999 · Pearl Purple | Multi-Pack Exclusive | X6999 | Pearl Purple | 2019 | |||
| MonopostoGJM54 · Light Blue | Mystery Models Series 2 | 12 | GJM54 | Light Blue | 2020 | ||
| MonopostoGJM54 · Light Blue | Mystery Models (2020, Series 2) | 12/12 | GJM54 | Light Blue | 2020 | ||
| MonopostoX6999 · Black | Multi-Pack Exclusives | X6999 | Black | 2021 | |||
| MonopostoX6999 · Black | Multi-Pack Exclusive | X6999 | Black | 2021 | |||
| MonopostoGTD78 · Black | Advent Calendar | GTD78 | Black | 2021 | |||
| MonopostoHFL03 · Metallic Dark Blue | Mystery Models Series 3 | 5 | HFL03 | Metallic Dark Blue | 2022 | ||
| MonopostoMetalflake dark red | Multi-Pack Exclusives | Metalflake dark red | 2024 | ||||
| MonopostoX6999 · Metalflake dark red | Multipack Exclusive | X6999 | Metalflake dark red | 2024 |
More from Advent Calendar 2021
Advent Calendar
This page last changed: Oct 10, 2026. The Hot Wheels database behind it is our own and is updated daily – releases from 1968 onwards plus our own unboxing videos.