The MINI V-DrillGuide is easy to use. Hold the drill guide on the material with the “v-groove” side resting on the drillable surface, clamp and drill. Use the drill guide on corners, round or flat parts. Twenty-one different hole sizes to use, including: #10, 21, 30, and 40. Other V-DrillGuides available too. Lifetime warranty and USA made. For more information visit www.biggatortools.com or call (888) 428-6748.