Apple has laid out its guidelines for third-party developers looking to make bands for the Apple Watch. The document comes with only two basic guidelines — the band must securely attach to the watch and not hinder its operation — but there are still plenty of other restrictions. Most notably, bands are prohibited from integrating magnetic chargers or using certain materials that don’t meet environmental standards. No mention is made of the watch’s diagnostic port, located in the slot where the bottom band fastens to the watch. Bands will have to fasten tightly enough to keep the watch’s sensors in contact with the user’s skin while remaining comfortable. The bands must pass corrosion tests and resist efforts to pull the band off, while still providing easy detachment when a user wants to remove the band. Apple provides specifications for creating the special lugs used to secure bands to the Apple Watch, but the homepage for the new guidelines says Apple will be making its own lugs available to developers soon through the Made for Apple Watch program.