Park Tool WAG-4 Professional Wheel Alignment Gauge - For 16-29" Wheels. For a wheel to perform properly it is important for the rim to be centered between the locknuts of the hub or “dished.” To check this and to make precision adjustments a wheel alignment gauge (also called a “dishing tool”) is a must. The Park Tool WAG is an accurate and truly versatile wheel alignment gauge that belongs alongside every truing stand.