Blake Lively wears a Casio Baby-G

Past the halfway point of The Shallows, Nancy Adams is stranded on a rock that low tide has left just above the water, a great white working the shallows around her. The film starts counting down the hours until high tide swallows the rock, and it does it through her watch: a translucent grey Casio Baby-G, its digital face blown up across the frame in picture-in-picture as the minutes run down. In the film's hero shot she checks it on her wrist and dives.

The watch is the Baby-G BG169R-8, resin case and strap, the women's offshoot of the G-Shock that Casio launched in 1994 to put the same toughness in a smaller package. It survives the ocean, the blood, and the shark unharmed. There is one catch: the BG169R-8 has no tide function. The countdown dial the film enlarges on screen is not the watch on Blake Lively's wrist; that is movie magic, not a Casio complication.

Nancy is a med-school dropout who travels to the remote Mexican beach where her late mother used to surf, planning to be alone with the waves. She gets the shark instead, and spends most of the film's brisk runtime in the water, timing the tide and staying just out of reach.