These locking knobs enable secure locking and unlocking of spindles with single one-touch operation and without the use of tools. Optimal for radial feeding applications (e.g., rack and pinion) and thrust feeding applications (e.g., leadscrew). Red and blue colors on knob indicate whether spindle is locked or unlocked. Perceptible "click" alert when locking and unlocking the spindle. Housing, boss and base are made from plastic. The insert is made from 304 stainless steel. Includes one stainless steel socket head cap screw and one stainless steel cup point socket head setscrew.