These devices are on the pool wall at both ends of each lane. Each pad is just one centimetre thick and incorporates sensors to detect a swimmer’s touch at the turn and finish. The time can be recorded immediately. On the surface of the Time Display Board are rows of small holes that dissipate water pressure so that the pad does not react even to a strong swirl of water. A signal is generated only by the swimmer’s touch.The time determined by signals from the touch pad is rapidly displayed on the scoreboard at the venue, and the swimmer can check his or her time right after the final touch. This information can also be used in live television feeds.

A video system is provided for each lane to enhance judgments on relay takeovers, and as a backup for time measurement. Previously these systems were only set up outside the water, but spray and so on sometimes made it difficult to verify a swimmer's touch at the turn and finish. Nowadays there are underwater cameras in each lane. These film the action below the surface, and supplement images from the cameras set up out of the water at either end of the pool. Each swimmer's fingertips can be monitored from above and below the surface of the water.

The starter lifts his electronic pistol high above his head, pulls the trigger-and they’re off! The sound of the pistol issues from a speaker built into each lane’s starting block. At that same instant the starting signal sets off the timer, which begins timing.

Each starting block incorporates pressure-sensitive sensors. At the start, the sensors detect the instant when the swimmer leaves the block. That information goes to the timer, where it is used to compute reaction times. Unlike in a track event, however, this data is not used to determine a false start. It simply serves as a point of reference, revealing who pushed off the block first. In swimming, a start is defined as the moment when a swimmer begins a starting action. Officials judge a false start not by considering when a competitor leaves the block, but by whether a competitor started to move before the pistol sounded. Reaction-time data is also made available to assist the judgment of a rule violation during a relay takeover.

This timer, used especially for swimming events, receives the signal from each starting block and Touch Pad. It measures reaction time, handles the lap count, and measures the split time and finish time for each competitor. Relay takeover times or takeover violations can be determined based on the difference in time of the signal from the Touch Pad and the signal from the starting block. A built-in printer can print out times on the spot.

SEIKO Underwater Lap Counters made their debut during the 2002 Pan-Pacific Swimming Championships in Yokohama. This system is used for events of 800 metres or longer. Every time a swimmer kicks the touch pad at the starting end, two laps are subtracted from the total lap count, and the number of laps remaining is displayed underwater. An LED display panel that operates in tandem with the counter is placed on the starting block at the turning end so that officials can check on the number of laps remaining.