11 1/2" inch 292mm drag bit/pdc drag drill bit for water well drilling 1.ISO9001:2000 2. ... 6, like mudstone, shale, sandstone, etc. mainly used for drain hole, grouting hole, geological and hydrology drilling, ... bits are three wings, while sometime people need for wings, five wings ro six wings.Our drag ... over.3. Fast penetrating two wing drill bit for wet drilling with centre flushing.4. PDC drill ...