You’ll be forgiven for being confused about which sci-fi movie sneakers Nike and Reebok have released and will release and when, because an amazing number of authoritative web news sources have repeatedly mangled the facts. Fear not, we’re here to help!

The Nikes You CAN’T Have: The 2015 Nike Mag

First up, you will not be able to buy a pair of Marty McFly’s iconic self-lacing trainers, as has often been reported. Those were actually an auction-only edition, with all proceeds going to the Michael J. Fox Foundation for Parkinson’s Research.

The Nikes You CAN Have: The Nike HyperAdapt 1.0

As Nike puts it “the shoe translates deep research in digital, electrical and mechanical engineering into…” Oh c’mon, Nike. Cut the crap. These are a novelty too. Yes, they’re self-lacing shoes, but this first version bears no resemblance to the Back to the Future shoes, and you still push buttons to adjust the laces! But you can drink the Kool Aid here, if you like.

The Reeboks You CAN’T Have: 2011 Alien Stomper

 

These apparently were never widely available, but that’s okay, they weren’t actually a reproduction of the shin-high sneakers Ripley wore in Aliens anyway.

The Reeboks You CAN Have: 2016 Alien Stomper

 

These are an exact replica of the Alien high-top Stompers worn by Ripley. Also being released is the mid-top version worn by Lance Henriksen as the android Bishop. The sneakers will be available beginning April 26, in honor of Alien Day, according to Hollywood Reporter. If you’re not nerdy enough to already have it on your calendar, the date is a reference to planet LV-426 from the “Alien Canon”.

The Converse Shoes You Might ALREADY Have: 2004 Chuck Taylor All Star Hi Top

We don’t know if you can still snag this particular vintage of Chuck Taylors in your size at a reasonable price, but we always thought it was pretty clever of the makers of I, Robot to make a movie in 2004 that’s set in 2035, so they could reference vintage 2004 sneakers, and then be able to buy them off-the-shelf.