Which of these bleeders are speed bleeders

Potentially each of them. Speedbleeders have a ball baering ckc valve, look for the ball at one end. They make multiple different sizes for different vehicle applications.

The ones that only flow in one direction -- could likely use a vacuum bleeder to verify if they flow in only one direction or both.

None that I can see. Those on the left are rear caliper, and on the right for the front.
The speed bleeders I have use a spring loaded conical tip, so loose like this and the tip would have separated.

Thanks. That helps a bunch….

hmm.

Speed bleeders I'm familiar with have a spring loaded check ball internal to them. Not in the tip. Probably multiple variants of the concept out there.

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What speed bleeder works best ?

I bought these along with some new ones for my 914 from the bird like 20 years ago. 914 originally had them (not sure of the brand, but they were rusted and stuck open). Replaced and never had an issue since.

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I never put them on my 930 because I started using a power bleeder. IMO best way to bleed and get firmest pedal.