As lubrication levels fall, friction levels rise, producing ultrasonic waves, which are very directional and localized. Easily attached to most standard grease guns, or worn in an optional belt holster, the Ultraprobe 201 Grease Caddy translates high-frequency sounds into the audible range, where users will hear and recognize bearing sounds. The Ultraprobe 201 Grease Caddy focuses on these sounds – even in the noisiest environment – and helps users identify when to stop lubricating.