Wide Range Industrial-Grade Digital Tachometers for Non-Contact and Contact Rotation and Cycle Measurements. The Hioki FT3405 and FT3406 are portable, contactless digital tachometers that use reflected visible spectrum light to measure the speed of a rotating object to which reflective tape has been affixed. The instruments can also be used as a contact-type tachometer by attaching the Z5003 Contact Adapter.