20-piece miniature drill set in plastic dispenser with one each of high speed twist drills in wire gauge #61 – #80. Drill soft metals, wood, plastics and acrylics for jewelery, bead making, model making RC/plane/boat/train. Any of these twist drill sizes can be used in the following Zona hand drills: 37-140 Swivel Head Pin Vise, 37-145 Double Ended Pin Vise. #61-#78 fit Zona Tool Holders: 37-120 and 37-130. #70-#80 fit Zona 37-160 Spiral Hand Drill. #61-#68 fit Zona 37-170 Small Pin Vise. They may also be used with other hand drills that hold wire gauge twist drills or rotary tools such as Foredom®, Dremel®, etc. with micro chuck. Click on the yellow chart at left for wire gauge dimensions in inches and millimeters.ll pin vise and other hand tools that hold wire gauges or in rotary handpiece with micro chucks.