If you've got a SX-70, you might be a little bummed that all special edition film packs are for 600 cameras only. But don't worry – these Polaroid Neutral Density filters slot over the top of 600 cartridges, changing how much light the film receives. And just like that, they make any 600 film compatible with SX-70 cameras.
They're completely reusable, too, so they should last for ages. Just don't throw them out with the cartridge when you finish a pack of film – seriously, it happens all the time.