Features: Micrometers are incredibly precise measuring tools used to accurately measure a variety of materials. The high precision of the micrometers offers machinists a versatile tool for creating high-quality final products. Self-centering 3-point for precision measurement. Especially helpful for measuring blind-bore. Ratchet stop head and carbide-tipped contact points. Resolution: 0.001mm (metric); 0.0001" (inch). A=0.5mm; L1 = 107mm. Metric Inch Order No. Range Setting ring Order No. Range Setting ring 107-1180 50-70mm 50mm 107-1190 2"-2.8" 2" 107-1181 70-100mm 70mm 107-1191 2.8"-4" 2.8" 107-1182 100-150mm 100mm 107-1192 4"-6" 4" 107-1183 150-250mm 150mm 107-1193 6"-10" 6" 107-1184 200-300mm Optional 107-1194 8"-12" Optional 107-1188 50-100mm (2pc Set) 70mm 107-1198 2"-4" (2pc Set) 2.8" 107-1189 100-250mm (2pc Set) 150mm 107-1199 4"-10" (2pc Set) 6"