Sources: Apple is developing prototypes for a screenless health and fitness tracker similar to Whoop but hasn't decided whether to release the product (Mark Gurman/Bloomberg)

Mark Gurman / Bloomberg: Sources: Apple is developing prototypes for a screenless health and fitness tracker similar to Whoop but hasn't decided whether to release the product  —  Apple Inc. is developing a screenless health and fitness tracker similar to Whoop Inc.'s wrist-worn device, part of an effort to rethink …