The KAT system has a suite of different devices.
The original KAT device is compact (2 in x 2 in x 1/2in ) and can easily be attached to the wearer’s body, tucked into waistband, sock, tight clothing or sport equipment.
Why aren't they smaller?
Because KAT is NOT primarily a data-collector; it is an Active Training and Feedback device. Vibrations are felt on the body through the surface area. This 2 x 2 surface area size allows for an optimal balance of 'felt sensation' and portability of the system.