Gym and classroom clocks
A large digital wall clock for a gym is read from across the hall during training. A large digital clock for a classroom is read by a whole class. Both are about digit size and readability distance, not about decoration.
Magnetic, waterproof and wall timers
A magnetic digital clock sticks to a metal surface. A waterproof digital clock survives splashes and damp rooms. A digital wall timer is the same large-display idea described as a timer rather than a clock. A digital kitchen clock is the smaller, domestic form of the same family.
What to confirm
Ask about digit height, readability distance, power source, and whether the display counts up, down, or both. Those figures are not stated on this site.