On Wednesday, March 13, 2019 at 10:05:35 PM UTC+8, Scott Dorsey wrote:
>
> I don't know of any mechanical pretensioners, although I would not be
> surprised if they existed in the transition period between retracting belts
> and the modern explosive pretensioner.
> --scott
>
I saw them in Youtube videos (by themself not in a car).
Just wondered what vehicles used them.
Presumably they were less reliable and needed a good housing to keep
dirt out.