Fastbox one - shutterspeed tester | Analogue camera

The FAST Box One is a shutter-speed tester
Thanks to its compact size, the FAST Box One is a companion for on the go.
Test a used camera at a flea market or check your gear after a long trip before inserting an expensive roll of film—sometimes it’s better just to be sure.
Also, the FAST Box One’s solid case has no cables hanging out; you just need a light source from your smartphone.